With the know your customer laws http://en.wikipedia.org/wiki/Know_your_customer it's increasingly the bank's responsibility to do the job of regulators. This is not new. It might be dumb, but it's how the system works(or doesn't work) right now.
KYC is about not doing business with terrorists or other undesirables. Madoff was not one of those. He was running a ponzi scheme but was otherwise an upstanding citizen. No bank would have any reason not to do business with him due to KYC due diligence.
I don't disagree that JPM has a responsibility to share any information they may have about financial fraud. I guess my point is that yeah, the $1.7B fine isn't much to JPM, but at the same time, it seems inline with their degree of negligence.