(Again I'm not an expert) With the Steam Subscriber Agreement it's effectively a purchase of a perpetual/indefinite license to non-commercial use of a game. But purchasing a DVD is, arguably, the same thing, you are given indefinite license to view the video non-commercially in a home setting. What difference does it make between a game on your hard drive and a movie on a disc?

By my moral standard, games with Steamworks bypassed by something like Goldberg is functionally equivalent to DVD decryption. It's my opinion that the continued access to social and internet connected features like Friends list, Workshop, Matchmaking, Redownloading games, Cloud Save Backups is contingent on accepting and adhering to your agreement with Valve and/or the server hosting the matchmacking service. That's why I'm very much against always online type of DRMs for single player games.

Imagine having a pool in your backyard, but the pool installers have to permit and supervise you while you use it. For a public pool it would make sense to be supervised for everyone's safety to ensure no one's messing around, but for your own pool it doesn't.