Ever since the bottom fell out of the financial markets in late 2008, Jamie Dimon has had one overriding message for Washington: Don’t crucify me for the sins of other banks. Or, as Dimon told me two years ago: “It’s never fair to punish everybody regardless of their behavior. There are good banks and bad banks just like there are good politicians and bad politicians.” Other megabanks had vaporized themselves by piling on preposterous amounts of risk—often risks they only dimly understood. But Dimon ran JP Morgan like the rector of a Catholic prep school, and the bank breezed through the crisis thanks to his exacting standards. He didn’t need the government second-guessing him.

During his extraordinary conference call Thursday night, in which the all-powerful CEO fessed up to a $2 billion trading loss, Dimon offered an updated version of his old mantra: Don’t crucify other banks for my sins. When an analyst asked Dimon if he thought his rivals might be sitting on similar time-bombs, Dimon shot back: “I don't know. Just because we are stupid doesn’t mean everybody else was.”

Suffice it to say, the proper response to the $2 billion blunder was not to tout the theoretical wisdom of other banks. It was to acknowledge that we now have ironclad proof—as if we really needed it—that everyone is capable of disastrous stupidity. But that’s the one thing Dimon can't admit, since it would require him to support intrusive regulations. Stupidity, in Dimon’s mind, is always isolated and explainable, not systemic and unavoidable.

Dimon’s refusal to see how the fiasco demolishes his critique of financial reform is really quite stunning. In fact, almost every mitigating circumstance he cited actually strengthens the case for reform. Dimon made clear that the loss wasn’t the work of a rogue trader: The position was completely authorized, he suggested, just poorly executed and weakly monitored. One shudders to think what might have happened at a less scrupulously-managed bank—of which there are many—when the losses could have escaped detection much longer.

Dimon said that, even after the loss, the company is on track to earn $4 billion this quarter, and that the loss barely dents its capital cushion, which exists to protect depositors, bondholders, and other creditors. Fine. But most megabanks are far less profitable than JP Morgan, and their capital reserves are less bountiful. The same $2 billion slip-up could have brought real distress to one of its rivals. Dimon also observed that “none of this has anything to do with clients,” by which he meant the firm had lost its own money, not customers' money. But if the loss had occurred at a weaker bank, it wouldn’t have mattered where it originated. The red ink would have engulfed both the company and its clients. Dimon’s pleas were reassuring only if you somehow think JP Morgan is the only fallible bank. But, of course, we know from experience that it makes fewer mistakes than most.