From today's L.A. Times, but it left me scratching my head

This article from today's front page states that people paying mortgages on underwater homes are creating a drag on the economy, because that money could be used to purchase other things.

I think the logic is a little tortured. It doesn't consider the fact that the vast majority of people are going to have to pay for a roof over their heads, whether it's in rent or for a mortgage.  So, is all money spent on housing a drag on the economy because that money could be spent on something else?