that it, in effect, makes illegal
I'm a bit confused by the whole concept of "cancel culture". You describe it as free speech being made "in effect illegal" by people expressing their concerns (eg, in this case calling for RMS to be removed from the board). But aren't they just as free to speak their concerns, as the speech that created the concerns? And isn't the board fully within their rights to listen to the those concerns and weigh them in their decisions?
Basically, is this actually a few speech issue, or do you just disagree with the perfectly legal decisions of the board, who are listening to the perfectly free feedback and concerns of the public?
David