So, if you buy bank shares today and it turns out the bank has been insolvent for 2 years already and management was hiding this from investors, this is totally fine, as long it's not an established bank but a "startup" bank, am I understanding you correctly?

Mark was in way over his head but nobody says he should be jailed for being in way over his head. He should be jailed for defrauding people. He cooked the books and he hid the fact that MtGox was insolvent practically from the moment he bought it.