Yeah the problem I see with this argument is that of course in an idealised world it would make sense to ban parts of the internet just like banning some kinds of oppinions is based irl.

But I think on the internet is a lot of garbage that has to be there so that people see it, because without allowing some garbage there is no discussion, no new values nor freedom.

I think any kind of left leaning ideology should enable non violent discourse as much as possible. Of course that would mean banning really bad things, but it would not mean complete restriction.

Also as a side note: Banning something does not kill the presence of it in society. In most cases it makes the issue worse than it is: You need more than just a ban, you need to convince people that you're right, not force them into beliving.

This is why fact based propaganda is valuable and a great way to stop populism.