Do you think we should pass a law forcing every online community to not have content guidelines?
Content guidelines are fine. But the way they are currently used -- where they can be so vague as to mean anything, and where things can change so dramatically after the fact -- isn't acceptable for any platform that basically constitutes a broad reach medium. It basically just devolves into a pretext for censorship in a broad reach medium. Get to a certain level of reach, and your content guideline means something very different than some little web forum tucked away somewhere.
So my answer would be this: It's disingenuous for someone to invoke "show you the door" if you're the only shop in town. If you're the only bakery in town, it's pretty crappy if you're not going to bake someone a wedding cake.
It's all contingent on reach. Buy one radio station, and only play fundamentalist Christian content? I think that's fine. But if you've bought 90% of all radio stations in the country? Yeah, I think the government might be doing us a favor if they called shenanigans on that.
Why?
Effective monopolies should not be able to shut down free speech.