In general, you don't have to worry about being banned for being bad. If you die because you're trying hard but you make a mistake, don't fret it. The only thing that can cause you to get banned is if you die intentionally.
The thread you linked is specifically talking about a player who is known to frequently use a strategy known as "Proxy Singed". This is a particularly strange case, because of the way Proxy Singed works. For teammates who don't know what you're doing, it looks like you're feeding. This can easily be countered by effective communication. You should also make sure you have buyin frim your team before you do any unorthodox strategies like this.
The main strategy of Proxy Singed is to run behind the enemy tower and farms the minion waves before they can even get to a useful part of the lane for the other team. Since Singed is the best at "proxy" farming like this, this will generally push your lane down very fast. Eventually, Singed will farm both the top and mid minion waves from inside the enemy base.
The obvious downside to this is that you don't really have a means to escape if the jungler or someone else comes to gank you, so you wind up dying a lot. You farm minions so much faster than anyone else in the game, however, that it makes up for the gold lost and gold given to the other team in many cases, as long as you never get a kill. If you kill an enemy champion, it will reset how much gold you are worth. Proxy Singed is effective because you are tanky, not worth a lot of gold, and hanging out in an area that is far away from important resources for the other team.
To your teammates, however, if they don't understand the strategy, it will look like you're just being an idiot and feeding.
I felt like it was important to explain the confusion for this specific case and how the player got banned despite trying his best because it really is a unique case and you shouldn't feel threatened that this will happen to you. If you want to try something extremely unorthodox like proxy Singed, warn your team about it. Otherwise, don't worry.