From the perspective of Twitter, the presence of groups you hate doesn't pollute the platform, it gives you something to engage with. From the perspective of civilization, it lets people get a little bit of perspective (including, in fact primarily, nuts).
It depends on what Musk wants to do with Twitter. If he doesn't care about profits and just wants to use it as an attention whoring outlet, then perhaps it doesn't matter so much, although I'd guess it's MSM being willing to publicize tweets that is the real attraction.
However, if Musk's goal (or, at least, one of his goals) is turning Twitter around as a company and making money from it, then keeping it family/advertiser friendly is very important. There's a reason Coca Cola isn't adverting on 4chan (or Truth social for that matter), nor is MSM promoting it.
Nobody cares about groups they hate being there. They hate groups they hate getting attention, and worse, people agreeing with them. And so those groups must go.
