What I meant was pretty much what the US SC expressed in Brandenburg v Ohio. In order for speech to be punishable, it must be "directed to inciting or producing imminent lawless action and is likely to incite or produce such action" and that "the mere abstract teaching of the moral propriety or even moral necessity for a resort to force and violence, is not the same as preparing a group for violent action and steeling it to such action."
Saying that there was mass voter fraud in Georgia is therefore not punishable speech.
edit: with Twitter and politicians, there is another layer. As Eddie, I think, mentioned there is already case law saying that (American) politicians can't block Americans on Twitter, because their speech is part of their performance of the constitutional mandate. This should be a two way street and there should be a corresponding obligation of Twitter and other social media with such dominant share of the market to not restrict politicians' speech except where it is illegal. I miss the days before social media too, but they are here now and excluding a politician from Facebook and Twitter has a massive impact on their ability to campaign. The advantage of a politician with access to them over one without it is so huge that it can't be dismissed by saying that in the olden days they didn't have Twitter either. Yeah, but nobody did.