How did the FSF imagine this would play out? The fact that RMS isn't really the kind of guy you want doing public relations work, combined with the cancel culture shitstorm that originally got him booted, should've been enough to make anyone think thrice before reappointing him.
If thou art not a witch, then drowning is an entirely appropriate option. If you float, you have revealed yourself to be Satan/Stallman's spawn, and thou shalt be hanged.
He's probably not the ideal public figurehead you'd want for the FSF, you can make a point that it'd be good if they chose someone less prone to creating controversies for the role, but frankly, the arguments in that letter range from inaccurate representations to complete lies, and no one should get cancelled for that.