I remember the opposite thing, politically, happening when Reddit clamped down on a number of rightwing -isms (and -philias) and then a site called Voat got created as the “free speech” alternative, except it only attracted the right wingers who saw the -isms as their core beliefs, and so the whole site was just that. Eventually Voat shut down, having failed to bring enough new to the table to attract regular, fairly politically indifferent folks