While your definition of censorship is correct, the implications are not. Only Government censorship is illegal.
I never said that non-government censorship was illegal. And I don't support attempts to make private party censorship illegal. Even rsilvergun got the reasons pretty much correct, that to do so you are infringing on the rights of those who own the platforms being used. (Stopped clock being right twice a day, I suppose.)
Now, the implications of censorship are bad. Of course they are, since censorship is an attempt to control how people communicate, and it pretty much never has positive results. Which is why rsilvergun and his gaggle of nitwit followers are so dead set on trying to redefine the word, because they know censorship is bad, and they want to censor speech anyway.