If somebody was being an asshole, what were you going to do? Wheedle your admin to tell his admin to take away his access? And how would your admin enforce that? Threaten to stop peering?
What happened was your admin told you to put the asshole in your killfile.
The only methods of enforcement between sites were either personal favors or the nuclear option of not peering.
But, The Cabal (which does not exist,) would smack people down if they became too outrageous. Not mere assholes, but people who ruin the commons for everyone...