The key, IMO, is ruthless moderation. If the goal is to get rid of the trash, then treat trash like trash. Issue it out with the rest of the garbage, without regard. It takes only a few mouse clicks to ban a member. It takes dozens of clicks to re-register, a new email account, and maybe even a new proxy to get past an IP ban. 99.999% of the trolls will go away after the first couple attempts, and the rest... well, just keep banning them. Its that easy. The people that want to stay will either modify their behavior, or they will be banned.
You might be surprised at how dedicated the opposition is to making sure they can keep coming back and causing trouble here on SnoWest, Ban or otherwise.
I am tracking 1,101 currently known "ALTER" accounts on SnoWest.
Those are all people who have come back in and created 1 or more additional accounts. Banning them doesn't stop them. Deleting them doesn't stop them. Banning their IPs doesn't stop them.
Those that wan't to cause trouble are highly motivated by their spite, hatred, Anger, animosity, ect, and take great joy in coming over here just to stir the pot and raise as much contention as they are able to.