agreed, but no law was broken, so no legal punishment is available, if moral failure was punishable, a certain president would have been held responsible for having banks make loans to people with no ability to to repay them, and the housing bubble mess would not have happened,
That's not quite how it happened.
There was nothing at all in the law forcing anyone to make bad loans to anyone.
The only requirement was that lenders could not discriminate on the basis of race, either by denying loans or charging higher interest rates on that basis alone. The problem was that proving that loan refusals or high rates were based on financial fundamentals and not discrimination meant red tape, documentation, and lawsuit defense. The solution was to direct everyone possible into liar-loans and hand them out like candy, both because the paperwork was simpler ("we don't discriminate, we fund everyone!") and because they were far more profitable. For what it's worth, the loans covered by the law actually failed less often than similar loans not covered by it.
And once they'd resold the loans to brokerages who bundled them up with insurance against default, they were off the hook for the risks. The brokerages were buying loans faster than they could be made, because by attaching the insurance and selling them on to investors in bulk, they had the risk hedged (or so everyone thought) and were making money hand over fist on these supposedly safe investment vehicles. The insurers (AIG, for example) didn't account for the possibility of entire regional housing markets collapsing, and didn't keep adequate reserves -- they weren't required to do so.
Lots of blame to go around. The overextended homebuyers were probably the least culpable -- lenders knew the risks far better than they did, and it's not a stretch to believe your lender when they tell you that you're good for a loan even when you're not sure about it yourself. And everyone knew real estate always goes up and you'd be able to refinance before the balloon payments kick in -- worst case, you could sell it and take the profits. Well, until the bubble popped, prices crashed, and refinancing became unavailable anyhow.