Because nobody actually cares about or likes the idea of free speech. Free speech is considered, at best, a necessary evil so that you can say YOUR point of view-nobody is ever really interested in an environment where people can say things that they find morally repulsive without consequence.

Which is why 'true' free speech platforms will always turn into a cesspool where rejects who aren't allowed to talk anywhere else will go to congregate…and then ban anyone who disagrees with THEM, because now it's THEIR safe space.