I think, though, that there ought to be a degree of respect and expectation on both sides. I mean, it's situational, but all parties have to realize it's about group consensus and it's highly variable.
Example 1: Folks in chat, couple of people come in, start getting amorous, person who doesn't want to deal with it asks them to stop, they ought to realize, Okay, well, yeah, not the place. And thus etiquette and respect win the day.
Example 2: Folks in chat are mostly engage in a freewheeling sexual reference orgy. Nobody's raised an objection as yet, and most folks seem to be into it. New person comes in, doesn't want to deal with it, but they're coming into an existing permissive situation that the consensus has demonstrably little problem with. My expectation is, in that situation, the newcomer, rather than shouting everyone down and demanding they stop, ought to think "hey, yeah, chat's out of control right now, I don't have the right to make everybody stop just for me, I'll just come back in 15, 20 minutes and see if everyone's calmed down yet." That also is etiquette and respect, in that the newcomer respects that the consensus situation in the chat when he or she enters is not to personal preference, and rather than single-handedly enforce a new "consensus," allows it to burn itself out (as it inevitably does) and doesn't get involved.
Problem with that is, there's no hard and fast rules on it. It's the kind of freedom we want, and the kind of mutual respect for both individual taste and the evolving group dynamic of the moment that we ought to have, but what can you do about the asshole who DOES want to enforce their singular will on a group of people who were doing fine all together before that asshole came in?