[simonh]

In China people can be sent to jail for 'causing destruction' but in western countries you have to have been proven, beyond reasonable doubt, to have broken a law.

Most of the activities the banks were carrying out that contributed to the crash were well known long before the crash, and were not illegal and they weren't being called out for it. In fact many politicians and the public were keen for broader availability of cheap loans. So yes, we need better regulation of financial institutions, but there were many causes of the financial crisis and blame lies in many places and many lessons learned, but you can't apply laws retroactively or arbitrarily.