I agree that nothing that happened last night is a big deal, I haven't seen anything morally reprehensible. I don't think people talking about drugs accuse the girls of anything since drugs since most of us probably experienced drugs at parties too.
However these apartments also dropped all pretense of real life a long time ago, which is fine. That guy being there was just really annoying because we have no idea who he is or his relationship with the girls, he's not dressed nicely like they are, he's just sticking out like a sore thumb.