This is an interesting comment. I suppose the NSFW factor has to do with the gaming being in private space or public space.
I think that's a big part of it yeah, though some pretty NFSW-adjacent games like Zenless Zero Zone are multiplayer, they're multiplayer in a way where other people don't interact with you much (if at all). That's more like horny dolly dress (which is absolutely a thing - just look at the mods for any highly moddable 3D RPG!) up than sex scenes though.
I have said this before, but this is why you could not "get away with" BG3 at the table: people like their horny fun in private or at least with very selective partners. No one wants to pretend to romance Shadowheart with their beer buddies.