I think that even if it did attract those who would be banned anywhere else, it would not necessarily mean it is not working - depends how you define "working". I see the problem with cancel culture in suppressing legitimate but unpopular opinions and polarizing society by promoting echo-chamberization. I would love to have a place where opinions would be discussed and voted down not because people do not like them but because they can find arguments against them in rigorous debate. But how to set up the system in such a way that it would distinguish and push to the most visible place the best reasoned opinions and not the ones most liked, that is the hard problem.