I've just been through this. Steam support are really good at sending canned responses and not great at actually doing anything. The winning argument for me was to quote the Steam subscriber agreement (my emphasis):
I was able to convince them to remove games I no longer wanted with a couple of exceptions where the game was part of a bundle and I wanted to keep other games from the same bundle.
FWIW The first canned response I got was identical to the OP's.
As requested by @LG102, here's the full email transcript with some sensitive stuff obfuscated...
1 Message by you on Tue, 31st Jul 2012 6:50 pm
I'd like to remove some titles from my library. These are games I
either don't like or will never play. Mostly, they came in bundles.
- Cosmic Osmo
- CS:S Beta
- The Manhole
- iBomber Defense
- Dota 2 Test
Many thanks
Apologies if this is auto-sorted to the wrong team but you don't have
any option that is a closer match
2 Message by Support Tech Raymond on Thu, 2nd Aug 2012 9:12 pm
Hello XXX,
Thank you for contacting Steam Support.
You are free to uninstall the game (right-click on the game name and
select "Delete local content") and change your game list to show only
installed games.
This can be done by clicking "Show" in the upper left-hand corner.
From here, select the "Installed" option.
Another option would be to create a new category for only this title
and then minimize the category. To create a new Category, please right
click the game and choose "Set Category".
Then click on the category name in your Library to collapse the
category.
If you have any further questions, please let us know.
3 Message by you on Thu, 2nd Aug 2012 9:33 pm
Thanks but a) Sorting into a folder doesn't work in "Tile" view and b)
That wasn't what I asked.
As per the Steam Subscriber agreement, (10.B)
"Termination by You.
You may cancel your Account at any time. You may cease use of a
Subscription at any time or, if you choose, you may request that we
terminate your access to a Subscription."
I'm making a request for you to cancel the specified subscriptions.
Are you unwilling or unable to do so?
4 Message by you on Thu, 2nd Aug 2012 9:35 pm
(To be clear, if cancelling any of the above would also cancel other
games, please let me know before proceeding)
5 Message by Support Tech Raymond on Fri, 3rd Aug 2012 1:45 am
Hello XXX,
Removing Dota 2 Test would require removing Dota 2.
Removing Cosmic Osmo and the Manhole would also require removing the
Cyan Complete Bundle. We do not have a way to remove individual games
from bundles.
I can assist you in permanently removing the game(s) from your
account. However, the game(s) will not be refunded and will not be
accessible for future use.
If you wish to play the games again you will need to repurchase them
from the Steam store in the future.
If you registered a game with a CD Key and we remove it, the CD Key
will no longer be valid and it will not be redeemable in the future.
Please let me know if you would like to proceed with the removal of
your game(s).
6 Message by you on Fri, 3rd Aug 2012 4:13 am
Hi, and thank you for the information.
Please remove Dota 2 (test and full version). Please do NOT remove
Cosmic Osmo as I want to keep other software in the bundle.
Please also remove the other titles mentioned.
Thanks for your assistance - much appreciated,
7 Message by Support Tech Mason on Mon, 6th Aug 2012 7:20 pm
Hello XXX,
Per your request, the titles/games have been removed from your
library.
Thank you again for contacting Steam Support.