Title? I don't need no stinkin' title.
Well, think about what you just said a bit.
If their is a social problem, it is the DM's problem. So, if a social problem comes up, a player by not being the DM, doesn't have the "role" of dealing with it.
That is where this idea of "social suppression" comes from. Because the player has this understood mentality that they are not supposed to get involved.
But, there is not a single real reason why a conflict at the table between two players has to be resolved by the DM. Anybody could handle that. But we default to the DM, because we think they have some extra weight or authority, whether or not they actually do.
That's putting the cart before the horse, assuming there is any "social suppression". I also disagree, groups can be dysfunctional for a lot of reasons including a player that dominates the game even though they aren't DMing.
I can only relay what I've seen. When there's a problem player there can be some feedback from other player but eventually it's up to the DM to deal with it. It's happened in games I've been involved with when I was just a player and when I was a DM. Without the DM there is no game, the DM can choose to not include the player in future games.
Ideally it would never get to that point, but then again if wishes were horses we'd probably be knee deep in horse crap.