Wow that was a long chicken and the egg debate. Was it loose lending, with the addition of some extra froth from flipping, that made the bubble so damaging? Or was it loose lending allowing flipping to drive costs to a bubble? Does it really matter? Both played this bubble. Do we really care if it was 60/40 or 40/60? Flipping wont work without loose lending, and loose lending will induce flipping in illiquid market like RE.

I prefer to think of it differently. Loose lending is like a gun, and flipping like a bullet. It was the bullet that killed someone, but only after being aimed and fired by the gun. Which one is to blame?
– Id argue the person who pulled the trigger. (Fannie/Freddie/Congress everyone is looking at you)