Generally, no. I think most have somewhat arbitrary criteria of being morally decent, but what that means to the individual in charge is as variable as the communities themselves. "Protected" notes keep things mostly in their place, on stuff intended for a smaller audience (with the understanding that anything on the internet isn't truly private, of course). Eveything else moves around more organically, through liking, reposting, and commenting.

Eventually you will come across topic-scoped relays and chat groups. Most clearly state their focus in the description and name.