RPGs are traditionally a game enjoyed by the socially awkward. For many of us, that means we don’t like interpersonal conflict.
I suspect my experience is common: in college, I thought mastering the rules of D&D 3.5 would give me the ability to make peace between killer DMs, power gamers, and other ne’er-do-wells by holding them accountable legalistically.
As a 40-something, that sure looks like conflict avoidance.
Don’t underestimate the power of pulling someone aside and diplomatically telling them they’re being a jerk. (And you don’t even have to be the gamemaster to do it!)
Furthermore, don’t underestimate the power of refusing to play with people who continue to be jerks after that.
For a lot of us, this seems unconscionable. Usually, you’re playing long-running games with your friends, after all. (And here the Five Geek Social Fallacies come into play, distorting how we think about those concepts.)
But life’s too short to play games with people you don’t or can’t trust. You can’t build strong enough mechanical guardrails to fix a lack of trust.