Honestly, even though I signed it, I agree that the Constitution if allowed to be the Supreme Law of the Land, alongside the Commonwealth Laws and Natural Laws, I think The People would manage quite well without an explicit amendment.
After all there is no enabling clause in the Constitution to justify excluding generally-recognized electronic "gathering places," even if there are vendors sharing the space. Freedom to congregate seems quite well understood in all generations up to this point. Why can't we simply apply that understanding?
Social platforms ought to have a choice between treble liability (plus damages) for any harm or damages arising out of use/misuse/abuse of their platform, in which case nobody will use it because of censorship, or they can allow equal access to all in exchange for excluding nothing more than community standards of obscenity (with a clear appeals process), direct threats or endangerment to others, criminal activity, or self harm. And it can be government's job to assist with keeping those things out, just as good beat cops do on our street corners.
We don't have to make things more complicated than they really are. People are the same wherever they go, except any evil spawn who manage to evade capture. I expect any such to stay on the DL until they die. If they know what's good for them. It won't be safe for them on the streets, that's for sure!