Why is camping generally looked down on in FPS/TPS games?
Some classes come equipped with long range guns that are nearly impossible to aim without stopping and aiming down the scope to spot an enemy (i.e. you wouldn't have a sniper class blindly running and shooting).
Why is camping generally looked down on in FPS/TPS games?
Put simply, camping isn't fun to play against.
Camping is a fairly simple, effective strategy when the game allows such a mechanic. It doesn't necessarily require a lot of skill to put a lot of pain on the other team when camping. People get frustrated and hurl insults when they're losing, especially to such a tactic that requires "so little skill" to pull off.
Another argument is that camping isn't fun to do, either, although this one is a bit flawed. Camping certainly is fun when it nets your team the win, because winning is fun. A better way to phrase it is that camping shouldn't be what's fun, because in theory the game should have more rewarding gameplay elsewhere. Direct engagement should be the most fun thing in a game, according to these people, and if you're camping you're "doing it wrong".
Snipers kind of have to camp; that's the basic gameplay of the class. It's frustrating to play against, so people rage out about it. Generally, though, even the best sniper can be taken out with just a little teamwork. Camping is a strategy, and like any strategy in a game, there are countermeasures that can be taken against it.
Camping is generally considered bad if there is little to no opposition you can form against said camper. There are several different cases, I can give you examples:
Spawn-Camping: Spawn-Camping is bad because usually, shortly after respawning, an opponent is still unprepared for combat. You spawn at a sometimes random location, you need to get your bearings, you take a couple of seconds to get your self familiarized, and before you are done, you are already dead.
Camping Snipers: This can be bad if there is no way for you to know where the shot came from. If you know where he is, it might still be difficult to oppose him if he has superior positioning. Some teammates might even protect a good sniper so he can't be flanked easily.
Camping areas: A lot of shooters have important areas that can be camped. This might or might not be part of the initial game design.
Now, you have two ways to look at it: Is it part of game design, or isn't it. Usually, spawn-Camping is looked down upon. However, in certain games and in situation in said games, it might be necessary. Case in point would be Team Fortress 2, where you push onto a last control point, and you are so close to the opponents spawn that you can just cut it out. In such a situation, spawn camping is necessary to win, however it might not even be considered camping.
In modern games where sniping is a core gameplay element, designers usually built in ways to counteract a sniper. These include killcams, scope reflection (seeing scoped in snipers), bullet trails, and more.
In general, if camping is not a necessity or part of the core gameplay, a lot of people look down on it because it is difficult to oppose campers that have superior positioning. Mostly, people are called campers because 1) they pick a class that has camping abilities, and 2) they are actually good enough so they can pin down a lot of people by utilizing said class. Usually, you won't call bad people campers because even if they have long range classes, they won't hit with it.
You can't looking at camping across all games, as different games are balanced to either encourage or discourage camping. I'll give an example of both.
In Quake 3, health bubbles, armor, and weapons spawn around the map on a set timer, requiring you to keep pace moving around the map to stay healthy, armored up and well equipped. If you were to say, camp the rocket launcher, you'd be missing out on the red armor and quad damage.
Alternate to this, in Counter-Strike camping is encouraged, but balanced. Since players don't respawn, theres a finite set of spots a player could hide on the map, and when pinched, a camping player can easily be hit with a grenade or flashbang into a vulnerable position.
There is no implicit social contract of games. If a player can take an advantage they will, and games where camping gives an unfair advantage suffer from a design flaw, not a player problem.
It depends on what you consider camping..
As others have stated, many times people complain about camping, when really the opponents are just sniping, or are just mad and want to find an excuse as to why they keep dying.
Sniping is when someone with a sniper rifle or another long ranged weapon sits in a well protected area with land mines/claymores/radars/etc. protecting them. This is not camping, as you still have to aim, etc.
Camping is when someone uses an ultra-close range weapon (such as akimbo machine pistols, shotguns, etc) and sits in a corner where he can't be seen until it's too late then just hits the shoot button.
Especially when using shotguns, camping doesn't even involve aiming. It's one of the easiest thing to do in most FPS games and it's quite effective!
The fact that camping involves such a small amount of skill with such high efficiency is why so many people hate campers (as it's kind of like a cheap way of playing the game).
Camping is breaking the implicit social contract of games, and inherently puts one player at an advantage because they limit their avenues of attack to the one that they're currently watching, and can only focus on that one.
Compare that to the other player who has to actively search out the player, opening himself up to an attack from all directions, having to look in a 360 degree arc around him, watching he doesn't get caught.
What I'm trying to say is that the camper has the advantage because most things that make a game challenging are removed when you hunker down.
Not rarely, camping is simply looked down upon out of frustration. When beaten, some players take comfort in blaming the game or the opponent. This has little to do with camping itself; the criticism could just as easily apply to backstabbing, stealth, spawn killing, blindfiring, rushing, bunnyhopping, grenade tossing, certain weapon types, strafe jumping, leaning, lag... No effectively used gameplay element is exempt from being considered 'cheap'.
Though sometimes the dislike for camping can be attributed to nothing more than a lack of sportsmanship, there are definitely reasonable complaints. Especially in early first person shooters, camping is a very useful strategy. So useful in fact, that every player aiming to win ought to employ it. The unfortunate outcome: the game enters a stalemate. The first player or team to break the stalemate, loses.
To keep these matches both fun and competitive, many players subscribed to an unwritten social contract: no camping. This line even made its way into many server rules. Ignoring the ban is frowned upon. Clearly, campers get an unfair advantage.
Even without these free riders, the social contract solution is less than ideal. David Serlin does an excellent job explaining why some bans don't work away from the casual end of the spectrum in his book 'Playing to Win: Becoming the Champion'. In particular, this chapter may be of interest. Because of referenced flaws, relying on players to voluntarily deviate from optimal strategies is considered bad game design and developers find a variety of ways to avoid it. E.g., in 'capture the flag' game modes, all-out camping is not a winning move. Optimal play does not cause stalemates.
In fact, stalemates are quite rare in today's FPS games. Nevertheless, campers maintain their bad reputation. Perhaps because players disagree with this assessment, perhaps because they missed the memo and look down on camping because their experience in gaming has taught them it is 'not done' for no particular reason.
Sniping and camping are really two different things. Anyway, both can be very annoying to the members of the other team if they cannot find a good way to defend themselves (which is what is unfair about 'camping', but is the purpose of sniping carried out in a skillful way).
If a spot is occupied for a long time in order to gain an unfair advantage, then that would qualify as 'camping' - e.g., if someone occupies a spot behind a spawn point and immediately shoots anyone who spawns. Doing that does not require much skill, but the camper is hard to combat, simply because noone can respawn. Therefore, this can justly be considered unfair and disruptive gameplay.
In contrast, a sniper might occupy a spot for a long time, where he/she can kill members of the other team from a concealed position. However, any skilled sniper will only stay at the same spot for a longer period of time to wait for a valuable target, but will relocate immediately after shooting once, or at most a few times. Any sniper that "camps" and attempts to shoot lots of players from the same location will probably get himself/herself killed very quickly, which implies that this sort of "camping" is considered bad tactics. Naturally, a skilled sniper can still annoy the members of the other team, because it can be very hard to combat him/her, but there is no unfair or disruptive gameplay involved in that case. Anyone can still respawn, so the other team can deploy counter-snipers, artillery or tanks (etc.) to fight back.
This is tough because there are many situations when someone gets called a "camper" and sometimes the complainer has a legitimate point, sometimes the campee has a legitimate reason to camp.
I think the biggest reason people complain about camping is because if a player, let's say his name is John, is running out in the open and engaging in some battle and then gets sniped by a camper, John sees this as the camper not really enjoying the game like he is, but rather just getting enjoyment out of the process of ruining someone's day. It's akin to a meter maid coming by and putting a ticket on your car for not following the rules. John probably shouldn't have been running out in the open like that when snipers can be nearby and the camper punishes him for it. If anyone here has played World Of Tanks, the arty players are seen in this way. They just sit back and punish other players for making mistakes, yet they themselves aren't really subjected to the same rules because they're way back behind the lines, camping.
The other reason it is frowned upon at times is that sometimes the team needs people to work together and make some kind of run for the enemy base or stop someone from capturing your flag or whatever, yet you have a team mate camping whom seems completely oblivious to what's going on and isn't helping the team because he's content just watching one hallway for example and will only contribute to the team if an enemy happens to come along at that exact spot. It's not efficient or particularly helpful in those cases and it's looked down upon at that point.