These folks engaged in acts that would be viewed as criminal in any other industry. It's not so much the loans themselves, but what happened after they were sold. The credit ratings assigned to CDOs and MBSs containing mostly junk were so off the mark that it's impossible to claim that they were realistic. There was clear collusion between the credit agencies, the banks, and the SEC. It's a shame no one has gotten more than a slap on the wrist.