Why wouldn't this apply equally to everyone who deposited money with Pirate? If we can assume that every reasonable person must have known it was a scam, then everyone who deposited money with Pirate was paying Pirate to steal money from others and give it to them.
Yes, all are responsible, but to different degrees. I make a distinction between individual, small-time fools and bigger insiders who make a huge effort to appear legitimate and use other fools' money to greater effect. It stands to reason that those who command and employ greater resources to help perpetrate fraud are more responsible.
Ponzi schemes make people irrational. Scammers know how to exploit that. I want people to learn a lesson rather than punishing them for being human.
Part of being human means using common sense. They were just recklessly greedy. Making people realize they could lose more than what they put in would do a better job.