This is overreach. This isn't giving speech to people under dictatorships, this is being the diktator. They, unelected, undeferring, are dictating the rules, regardless of local laws, mores and so on.
If they continue setting the rules for speech world-wide from their world-view-only, I think we can expect to see more Nigerias, Irans and Chinas when it comes to Twitter --and I would not blame them. Arguably, they are interfering with the sovereignty of these places. Ten years ago people who like this sort of pannational rule setting would have been claiming "Imperialism" but it's okay because they are the imperialists.