A real good friend of mine lost their posting privileges on Twitter today and they brought up the First Amendment again. I decided to use my "that's a shame" and "oh wow" looks, because I didn't want to explain exactly what the First Amendment says.
"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances."
The last time I looked Twitter, Facebook, and other social media platforms including this one are not arms of the the U.S. Congress. And before joining almost every social media platform, we must agree to the site's terms and conditions. IMO it's really simple; if we want to post or tweet, we have to agree to their terms and conditions.
I suppose there are a couple of "no holds barred" social media sites, but probably not very many.