I agree with him on the fundamentals of free speech and censorship but I think some of his opinions are misguided.  The first amendment applies to the US congress and not private companies like Google or Facebook and tbh the only way to make it apply to them would be for them to be state owned. I'm sure you can appreciate the problems that would come along if that was the case.

Point being, Google, Facebook and all the others have the right to deny access to their platform as they see fit.  That's not to say that I think they should, only that they legally can.

I don't really see how it can be stopped other than by boycotting their services.