I would disagree. When someone is young, most of the time they have some education debt that they have to pay off for school, but when they're buying a home, it's usually because they're on a path. They might get a promotion, etc.
Also, the baby boom generation got into the market knowing what the risks were and made sure they could make those payments, even when they were dealing with double-digit interest rates. Again, I think the policy somewhat smacks of the nanny state.
What evidence does CMHC have that supports your contention that portfolio insurance has distortionary effects that are stimulating excess credit and contributing to higher levels of household debt?