No need to blame the banks. It was a systemic problem that was not created exclusively by the banks (Ratings agencies told them the risk was low), by finance (derivatives are actually an excellent financial tool when used intelligently), by government (government backed credit has been used since time immemorial, some for good some for bad, regarding both intention and result), by salesmen (the micro-economics were sound), by buyers (again with the micro-economics), or by the ratings agencies. I don't have a comment for the last one, as they (much more than the SEC or any government agency) are the watchdog for these situations. If there was any misdeed, it was that the finance guys felt good about creating crazy derivatives while the ratings guys felt good about rating them.
Yes, some people in this huge equation were malicious. They can be found in each and every corner. And they would have gotten away with it except for the crash. Justice for any who committed crimes, but blame none if not the whole for the crash.