In fact most Lemmy instances have a pretty bog standard terms of service/community rules/whatever that specifically say this, yes. That not only must they abide by the rules of their instance but that they must also abide by the rules of the group.

But this concern troll (who is certain that we're "making feminism look bad" by telling men who barge into a women's space uninvited and against the rules to fuck off) barges into a women's space uninvited to concern troll and is shocked ... SHOCKED! ... to find that some of us are fed up to the fucking gills with his kind and tell him to fuck off.