I could bet money that the opposite of what you're saying is true. But I think that illustrates a much bigger problem. The society is so polarized, that we can't even agree on basic facts. Something went terribly wrong with the internet and the media and now we're living in two completely different realities, that are fundamentally incompatible with one another.
Yes I think Facebook allowed the Fauci threats as PR to make themselves look neutral. Mark Zuckerberg and his employees have been playing good cop bad cop with us since the beginning to make the public perceive Facebook as a neutral bystander when in fact they're in a large part responsible for the whole mess and are not neutral at all.
You're right, they technically don't. But they ban everything that can be even remotely interpreted as "offensive". To give you one example, I got banned for pointing out the appeal to nature fallacy. I've said that rape and murder is technically natural and yet it's not socially acceptable. Literally just that. Nothing less, nothing more. But someone either misinterpreted that simple sentence or found it offensive because of the context of the conversation, and thus I got banned.