Probably whoever is sufficiently bothered by their behavior first. Otherwise I assume they read here: [agnostic.com] and interpreted it well enough.

If I have a personal objection, I state it specifically. If I see someone else being treated badly and the other person hasn't said anything, I might say something like "I'd consider that rude if you said that to me" - possibly just a little less politely, depending on things like if I'm still experiencing nicotine withdrawal... and if the other person has said something but the objectional behavior is still going on, I'll step in with words about what is or isn't okay.

I would not dare to speak for the whole group. Admin can do that if they want, but that's not my place. Under a really rare circumstance, Imight take the furthest step of "I don't see anyone who approves of what you are saying" - which leaves open a spot for anyone to say "hey, I agree with the other person's position" - probably phrased in a less nerdy way.

Just be polite & respectful & you'll be fine.

Definitely don't post too many dick pics. Leaned that the hard way.

The same as any discussion group - use I statements and never personally attack someone. I feel everyone is entitled to their own opinion. Lot's of good discussions, good groups and great people. Welcome.

I speak to my own experience rather than advise people of theirs. Seems to generally work.

just be yourself, be honest, that's it