I'm all for tax breaks, but not stupid ones like this one.
Let me see if I can understand the logic behind it: A person buys a house, and the value goes down. Poor, sad, person. Lets let him deduct that loss from his income tax to make him feel better.
But to take that same, idiotic logic a step further, why not do the same thing for other investments? 401(k) go down? Tax deduction! Buy yourself some green energy stocks that tanked? Tax deduction!
But that's not how life works. Sometimes you buy things, and they lose value. This does not require a freeking tax deduction. If you want to reduce taxes, just lower the rate. Stop it with the complex, surgically targeted deductions.