The legal questions of what FB’s rights are to control their platform are irrelevant to a discussion on the merits of how they choose to do it (and I’d suggest aren’t as clear cut as your implying).

If you’re isolating, then you also can’t catch coronavirus from somebody attending a protest. If you’re out in public, then you could also be randomly struck by a car (unintentional injuries are the 3rd leading cause of death in the US). Do you have the same view on advertisements for Ford?

These people are exercising their constitutional right to petition their government. Facebook is trying to prevent them from doing it because they don’t want them to. No matter how justified you think that is, it is anti-civil liberties, and anti-democracy. They are also doing so (at least according to the reports I’ve read), under the guise of preventing misinformation. Again, no matter how justified you think it is, it has nothing to do with misinformation, and is a clear signal of how they intend to apply “misinformation” moderation.

The problem that underlines all of this is that no private organization should have the power to control citizens to this extent. Regardless of what you think of these protestors, Mark Zuckerberg should not be the final arbiter on whether or not they’re allowed to organise themselves. HN and many other communities like it are very vocal about what services people should have access to, things like housing, transport, healthcare... but for speech all of a sudden we need a central authority to determine who’s worthy of access.