> and you will be responsible for further
They didn't suborn the behavior, they just acted as a carrier for it. And if they didn't, it would find other outlets.
> in the worst case scenario
The worst case scenario would be someone using your platform to organize a genocide, not conspiracy theorists communicating ideas to each other; and since Facebook apparently didn't feel too embarrassed about allowing the former the latter barely seems worthy of consideration.
> On the other hand, if you do censor, you piss people off anyway.
And you drive them further down the rabbit hole, where true monsters like to gather and feed off their isolation and bitterness.