You can’t force collaboration
You can. There's always the lowest common denominator. If there's a guy peddling viagra pills in the astronomy community, it's clearly offtopic. Most mods would flag the post regardless of their political or ideological affiliation. That takes care of the obvious spam.
- cooperation = advantage
- noncooperation = no advantage nor disadvantage
instances that have different views and rules on moderation
And that's ok. They will do as they always did. Hide posts, or users that violates their terms of service
- cooperation = advantage
- noncooperation = no advantage nor disadvantage