A lot of people have been concerned about a bursting housing bubble happening once interest rates start to rise. Even if that happens it wouldn't necessarily be such a big deal. But, if a large chunk of our population got suckered into getting variable rate mortgages so they could go from buying a house the couldn't afford to buying a house they REALLY REALLY couldn't afford, the impact of an interest rate rise could be, uh, bad.
Here's the deal. Interest rates go up. Your housing price falls. Your mortgage payment goes up substantially. You can no longer afford to make your mortgage payment. And, since the market value of your house is now less than the value of your outstanding loan, you can't just sell and trade down. Default. Foreclosure. Cardboard box.
This is another facet of the ongoing War on the Middle Class that the administration has been pursuing for ideological purposes. Forget the phrase "starve the beast" - that puts an implied value judgement on the government, which often is the sole bulwark protecting and encouraging the growth of the middle class. War on the Middle Class is more descriptive because it's at the expense of the middle class that the corporate welfare state is being funded.