> What was a lot harder were the toxic users that just stuck around. Not doing anything bad enough to necessarily warrant a permanent ban, but just a constant stream of shitty behavior. Especially sometimes when the most toxic users were also some of the most popular users.

What people find out, again and again, is that you just ban those users. Don't need an excuse. Just ban them. Even if they are popular. Your community will be much better once you do.