Dr. Boys was specific, not general in his comment. He speaks of a specific type of loan and what affect it had on the home values of some people. And he spoke the truth about it.
If so, he’s an idiot anyway. The loan doesn’t affect the VALUE of the property. The EQUITY, yes. VALUE, no. He specifically said they were worth 50% of what they were, that’s a value indication, not equity.
And if you mean Neg-Am Option ARMs, it’s still nowhere near a 50% reduction in equity.