You can't. Not without banning those responsible for that kind of behavior or severely dis-incentivizing them somehow from coming to the community.

I think more generally, if I understand what you mean correctly, that that is really nothing more than water-cooler talk. Talk meant to be pleasant rather than investigative.

I also think with that said, it's really only a property of small communities because once it reaches a certain size, the amount of substantive things to discuss and hash out doesn't scale with the number of users.