Jamie Dimon is no idiot. He spread Bitcoin FUD for his company to be able to buy bitcoins at lower prices. That's a smart move. Fraud would be a far more accurate adjective.
that's one way to look at this scenario. but we really don't know what his real intentions are.
and yes, you can't call a person an idiot just because he gave his opinion to something. we don't know him personally so he might have reasons why he said that. at the end of the day, we're not giving him money to buy his food, right?