(There are actually plenty of high score borrowers that did get fooled into toxic loans)
100% financing was brilliant!
Mortgage interest is some of the cheapest money that you can get. There are people with high credit scores who financed 100% just because they could.
Their cash is worth more to them than the rate on a 20% 2nd.
Many people put money down only because they think they should. Others understand the OPM game and put thier cash to better use.
Many people who have paid principal into their homes are losing it all anyway. With an interest only loan, they would be walking away from less out of pocket cash.
The more cash they put down, the more they will be walking away from.