Can you regulate an unorganized message board? If the guys at WSB are telling people what to do, and it is open to everyone to read, there are free speech issues with saying they can't do this. They aren't taking their money and doing this. Also, they aren't themselves investing the money. It is a message board. Unless there is a coordinated effort to pump and dump, which doesn't appear to be the case, then i am not sure how it is manipulation.
They took data, found an inefficiency in the market, and recommended that money can be made by putting on a short squeeze on. I think that is fair. Hedge funds shouldn't expose themselves to that.
You play the game, you sometimes lose. Just because you are "important" doesn't innoculate you from the irrationality of the market.