How are you being forced to use Steam to buy your games?
Because I don't "do" piracy. Unless you mean the choice of game I want to play isn't important, but personally I wouldn't want to replace Half Life 2 with Halo or New Vegas with Big Rigs. Call me picky if you like.
Or are you talking about Steam being used as the DRM for a game? If you are, therefore you should also be complaining about Securom, Tages, and other forms of DRM as well.
As I do frequently. But that's not what was being discussed here.