I definitely understand your perspective and such mirrored mine for a long time. I will also be the first to concede that if the first amendment doesn't protect this kind of speech, then really, what does it protect?
With that said, we have to understand that large swaths of the American population get almost all of their "news" from the figures they follow on Facebook and it ends up codifying the belief systems by which they live their lives and make decisions. So when you say:
> You have to show some evidence for a wild claim like that, because you're insinuating that Paul Joseph Watson and Milo are getting people killed.
Well, I don't really understand how you can claim that anti-vaxxing views are not dangerous. We enter social contracts with each other when we enter into public spaces and we should have the right to ensure that others won't intentionally get us sick. I'm not sure whether or not the aforementioned characters have a specific stance on anti-vaxxing, but they definitely are responsible for spreading other types of equally dangerous ideology to millions in ways which have hurt and killed many (Alex Jones being the preeminent example here; my otherwise levelheaded friend bought an AK because of him to prepare for the upcoming class warfare). And this is in Seattle. Just imagine the kind of behavior you can expect to see inland when these kinds of nutty beliefs are bolstered by their local social popularity.
We have to understand that other members of our populace don't have the facilities to be able to separate fact from fiction and these people specifically are the most vulnerable to adopting beliefs that weaken the social fabric of our society, making our country more hateful and divisive. Again, I think free speech is important, but speech that is intentionally misleading and that sews hatred and violent tendencies needs to be examined closely.
I think Facebook has probably extrapolated the siloing effect that social media has on groups forward a few years and come to the conclusion that certain groups (namely the far and alt right) base much of their ideology on not only hate, but conspiracies and misinformation. This will eventually come to a headwind in which domestic national security in our country begins to look more like the middle east and that is something that we should try to avoid.