It has been shown time and time again that giving unrestricted uncensored access to billions will lead to the worst ideas proliferating. Look at QAnon and conspiracy theories running wild. Look anti-vaxxers and how America, one of the most advanced countries in the world, is now having Measles outbreaks after decades of having nearly 0 cases. Look at how simple things such as wearing a mask has become a controversial topic.
Yes, everyone would obviously prefer a fully open and uncensored platform, but the reality is that those are very easy for bad actors to take advantage of. So many things on the web is disappearing thanks to these bad actors. Public APIs are getting locked down, Catpchas everywhere, passwords and 2fa are getting increasingly more complicated, and so on.
If you really think every platform should be 100% open, you live in an idealistic universe that is not this one. The whole idea of "the solution to bad speech is more speech" simply does not work. It just doesn't.