Elon Musk's tweets were fraudulent in nature — he intentionally posted untrue information in an attempt to squeeze investors who had bet against the company. Musk acted and continues to act recklessly and needs to be held accountable for his actions, especially in this case as his irresponsibility lost investors their money.
Musk's tweet was not fraudulent — he had no ill intent and simply wanted to inform shareholders of his plans at the time. Musk knew he could use his own wealth and involvement in SpaceX to take Tesla private if he needed to. Musk does not deserve to be penalized just because the deal didn't go through.
There is a 28% chance that Tesla will become the largest car company in the world (by sales) before 2035, according to the Metaculus prediction community.