You can be DRM free and still require Steam.
DRM is designed to protect against piracy and copying. No one would have issues with DRM is it always worked and never gave anyone issues or problems. Requiring a support library is not DRM.
I understand many DRM-haters still think of that as DRM, but it really isn't. It's like saying a game that requires Windows 8.1 to run is DRM protected because I can't play it on Windows 7.
Well, I don't mean to re-open the Steam/DRM debate, but I think that anything that Manages your Rights to play Digital content is DRM (see what I did there?). If you can't reinstall a game on another machine (or hundreds of machines), sell it, trade it, etc., then your Rights to Digital content have been Managed. It's more than requiring a support library-- it's validating (based on Steam login) that you've bought the game. You're not even buying a game-- you're buying a license to play the game via Steam. Because of this, even if DRM always worked (which for Steam it almost always does), I think it's false to say that "no one would have issues with DRM."
I do think that the reason some people are opposed to DRM at any costs is because of the checkered past of DRM, but that's beside the point.
But like I said before, I don't have a problem with Steam's level of DRM, given the value-add of the Steam platform and that it protects the developers from piracy (as you say).