If it was to try to prevent the board becoming a useless vestigial organ incapable of meaningfully affecting the direction of the organization, it sure looks like they were right to be worried about that and acting on such concern wouldn’t be a mistake (doing it so late when the feared-state-of-things was already the actual state of things, yes, a mistake, except as a symbolic gesture).
If it was for other reasons, yeah, may simply have been dumb.