The SFC is a bunch of wacko's and they cannot speak for the free software "movement." Last I heard about them, they were mad about somebody suing for a GPL violation.

Never heard of them, but wasn't impressed by their credentials. Not going to be give much weight to a random system administrator and high school teacher. If RMS can be attacked for his prominence in computing, then I can similarly undermine his attackers for their lack thereof.

The SFC isn't a bunch of randos -- they handle the administrative end of things for a whole bunch of high profile foss projects:

https://sfconservancy.org/projects/current/

Half of their staff has worked for the FSF in the past. More than one of them has given a keynote at the FSF's anual conference. These folks are tightly integrated into the bits of the free software movement most closely associated with RMS; the fact that they've come out and said this is a big deal.