Why do so many people complain that you have to be online to play steam games? For something that is just straight up not true it's a little strange how many people complain about it.

Steams DRM is pretty shit, too, but yeah, the offline mode works. I did have a problem awhile back where it wouldn't' work unless I turned auto-update on all the games off, which you can only do while logged in.
 
EDIT:
And I'm not sure what the point of the "well then, don't buy it!" argument is. I don't intend to.

I could point out all the differences, but instead I'll just say this: 
 
The reason behind the internet connection. Steam may get the added bonus of this being protection, but that's not the point. With the DRM it is. Oh, and you can play in offline mode. I'm aware this has been said. It apparently needs to be repeated.