All large sites have terms of service. If you violate them, you might be removed, even if you're "the dominant electoral candidate". Remember, no one is above the law, or in the case, the rules that a site wishes to enforce.
I'm not a fan of political censorship (unless that means enforcing the same ToS that everyone else is held to, in which case, go for it). Neither am I for the radical notion of legislation telling a private organization that they must host content that they don't wish to.
This has zero to do with net neutrality. Nothing. Nada.
Is there evidence that the government leaned on a private company instead of meeting with them and asking them to do a thing? Did Facebook feel coerced into taking actions they wouldn't have willingly done otherwise?
What you should ask yourself is this: irrespective of whether compliance is voluntary or not, is political censorship on social media OK? And what kind of a logical knot one must contort one’s mind into to suggest that this is the second coming of net neutrality? Personally I think the mere fact that the government is able to lean on a private company like that is damning AF.