Government does, but other entities don’t.
I am not saying I agree or like it, just that 1st amendment doesn’t specifically apply here.
The general idea of freedom of speech applies and there may be state, local laws or other federal laws in play. But that’s more “in spirit” and wouldn’t hold up in court.
It’s like people being censored on Facebook or YouTube - “Don’t like it? Build your own Facebook or YouTube, pal”. Here it’s “build your own MSG, pal” I guess.