The statement in question reads:
> Perhaps the more pertinent question is what if the US gov doesn't recognize the risk and allow insurers to raise rates.
Breaking it down: if the US gov (or its subdivisions) believes the risk is "gouging" or "egregious" or "too expensive" and prohibits rate increases, an insurer thinks they'll lose money, and leave the market. When this happens either the gov steps in as an insurer of last resort (and loses tons of money, because underwriting isn't a political problem), or insurance products cease to be sold in that area.
If insurance is no longer available, the house is no longer eligible for a fannie/freddie conforming loan, and is for all practical purposes ineligible for a mortgage. The local property market dies overnight.