Fined at worst. Jail is absurd unless he, like, sold a bunch of shares at the top or something (which he didn't).
You're absolutely right that this shouldn't matter. But since charisma _does_ matter, the SEC just has to paint him as an angry anorak trying to punish short sellers. I don't think that picture is hard to paint (I can't see into his mind, so obviously I have no idea if it has even the smallest element of truth).