This is a shortsighted take IMO. "Fringe" websites are growing rapidly while engagement on the big, normal websites is declining or slowing down. The problem is people want to talk about these things, and if that's what people want to talk about they're going to go where they can talk about them. This is directly addressed in the article (when we say we want to ban hate speech, what we really want to ban is hate, but hate cannot be banned). These big legitimate sites only feel permanently dominating now, but are not permanent by any means. People don't go on the internet and talk because talking is a way to use Facebook, people go on Facebook to talk about what they want to talk about. If people want to talk about edgy or even hateful stuff, they will, and if they can't do that on Facebook they'll do it elsewhere.

That's not to even get into the fact that all to often these terms like "fringe websites" are used by entities to shame users into not using their competition, which further degrades the integrity of any anti hate message.