Is that an edict handed down from on high? The majority has the power to enforce rules (they can impose social consequences on rule-breakers) and they usually have a good deal of wisdom about what rules are worth enforcing. They clearly do enforce them, and who says they shouldn't?
I think the fundamental reason that they should is that players are the ones playing the game the most, and in my experience, the most active players usually have a more accurate understanding of what's fun and what's fair than the game designers.
I don't condone death threats; bad behavior comes in all flavors.
No. Any decent multiplayer game is designed and, when necessary, updated to prevent or permit certain actions.