I know from personal experience that this is exactly wrong. Most of the left-leaning blue-checks that I followed on Twitter became mastodon users starting about a week after he carried the literal sink in through the door. It accelerated during subsequent events. While I still laughed when Paul Ford recently characterized Mastodon as "socialists who solder", the truth is that far more ordinary folk than I thought possible made it past the senseless UX hurdles that Mastodon makes new users jump over right away. I was amazed.