are you actually banning people or using automod to automatically remove their posts?

There's no benefit to banning the bad folks, since, like your guy, they just create a new account.

    author:
        name: [baddude1, baddude2]
    action: remove
    action_reason: "Troll / Spammer"

In my subs, this one condition does the most work. I also filter off low karma and new accounts to prevent spammers, trolls, etc.