The MEA game ratings thread (ESRB rating description)

The meetups in the Citadel DLC are all optional; that is, you can skip over them and still invite that character to your party.  So, drinking with Miranda in the appartment and at the casino are optional; the drinking contest with Ashley is optional, as is the drinking scene at the bar with Wrex, Garrus, and Joker.  In addition, in those last ones, Shepard is not shown actually taking a drink.  For the party, the player can opt to have a quiet party and serve food instead.  Here, Shepard will accept a drink when he/she sits down with James and company in the living room, but he/she is never shown actually drinking anything.

I agree that some inferences of Shepard drinking are still there, but it's certainly not what I would describe as being "forced" on the player.  The entire DLC is optional.

Overall, I find the swearing pretty minimal in any of the ME games as well.  Some of it is certainly avoidable by selecting different lines.  All in all, I think most of the swearing you're hearing comes from the mouths of the NPCs.

... and the game is rated in a manner that accounts for the language and alcohol use... so, anyone who truly objects to it completely can avoid purchasing the game.  That's why the rating system exists.