I think he’s doing what’s necessary. It is hard, hard work to get men to follow you after a defeat as comprehensive as the Battle of the Blackwater, and after the Battle of Castle Black and knowing you’ll need them again and again, yeah you’re going to want to keep them loyal.
Keep in mind, ALL of the castles he was talking about belong to the Night’s Watch, so while the Watch would be pissed, they also A. don’t really have anything they can do about it, and B. owe him their very lives. As for the Northern lords, they might not be super happy that traditions are being flouted, but they themselves aren’t losing any land, so they’re unlikely to start a ruckus.