The problem there is that these sites have become echo-chambers, where they breed extremism. These kinds of ideologies (E.G. Nazism) need to be exposed to the light, like a bacteria, in order to be shamed and debunked.
If I go to a bar and there's some guy screaming about his Nazi ideology and the owners don't kick him out, I'm going to just move on.
If some social media platform is full of trolls and hatred and such... people are just going to go away. It becomes a 'race to the bottom'.
Instead what seems to happen is that normies get pulled into Nazi content because the recommendation algorithms on these sites see heated discussions as engagement and try to feed it.