Has anyone commenting here even read Elon's tweet in question?
"Nothing stopping Tesla team at our car plant from voting union. Could do so tmrw if they wanted. But why pay union dues & give up stock options for nothing? Our safety record is 2X better than when plant was UAW & everybody already gets healthcare." - Elon, https://twitter.com/elonmusk/status/998454539941367808
Edit to add: lots of Elon hate blocking critical thinking here on HN.