My point wasn't that people weren't mean to her, it was that it didn't work. In the end we gave up and banned her because she was harming the forum.
So if there were a user who, without directly violating the rules of the forum, posted disproportionately, and was the loudest voice in a ridiculous number of threads, and regularly made other people uncomfortable, and whose posting changed the character of the forum so that regular users were uncomfortable here and kept leaving... I am to believe that the mods would be on top of that and would find a way to restore balance? At that at no point it could come to people being mean?
We're all human. I'm not going to pretend I'm morally superior and have never been mean to someone or that others can't be mean, because we all have buttons. With that poster, I think I trolled her by posting memes after every post in a certain thread of rolling eye gifs because I was at my wits end with her and wanted her to stop trolling all of us. (She may have been in need of professional help, but she was also a troll.) Was that mature? No. But I was uncomfortable and it restored some type of power level balance for me as a poster. Someone had invaded my home and was making it unpleasant and the only solution I could find at the time was to make it equally unpleasant for her, which many others did as well.
If that were to happen again, at no point could people become mean? No. I know we encourage good behavior, but people are emotional creatures and it's ridiculous to think that no one, out of all of this people on the board, will become mean. Our job, the moderators, is to try to stop a situation from getting too bad, but sometimes we get there too late or in some instances only make it worse and then we have to stop and clean up the mess. Personally I would never like to see people leave because of one or a few asshats ruining things for the majority, but I don't think that's going to happen.