"Are the MM's REALLY that stupid?"
No, they're greedy. Even "professionals" get greedy. Blinded by greed, they have sold shares to the public that don't exist. They have gotten away with it for a long time, and expected to get away with it this time, too. However, they are now confronted with a problem: An unexpected new circumstance, which exposes their wrong doing, to which they have no new answers, only their old tricks.
"that professional MM's would do anything to put themselves in a position to go broke!"
No one is going broke. 99% of the time they get away with it. Losing on one short squeeze is part of doing business.