The fact is tho, Massie can just, say whatever he likes on the floor of Congress. They can't arrest him for that. Now they might, but they can't do it legally - it'll be another overt Hitler act for Trump. Furthermore, if enough ppl reprint what he says, while immune, they probably don't have the resources to prosecute everyone.
So if Massie IS serious? He can hurt Trump now. Or at least galvanize the idea that the only way out is a fight. Just don't bet on fucking ancaps/libertarians man.
I assume however, because Massie is not an idiot, just a monster, he does understand that doing so will be playing with his literal life. So... I just I dunno mates. I have never had much luck betting on whatever shared ideology we have with libertarians and ancaps. And it's really not much - really basic shit like you "no death camps." It's not much.