@MrSchism: Maybe, but that one is closed. So either reopen this one or that one, thanks. I think saying "it's a feature" (basically what @slouken said in #505) isn't an appropriate solution to this.
They said (in short) that it'll be solved once TF2 moves to the new format. That's a solution for the issue coming down the line (undisclosed timeframe).
Nothing extracted yet.
Today I uninstalled Team Fortress 2 Beta. It was removed and marked as Not installed in Library. But there is still 1.1GB of files left on disk, which were not removed.
System info