I am all for eliminating mortgage interest rate deductions. It primarily benefits upper-middle class homeowners. They borrow money from a bank and somehow get a tax break for it? Yet, even a wealthy person that pays cash for their home doesn't enjoy that benefit?
I think the idea is to encourage people to invest in non-liquid assets, in order for them to save rather than to spend. Also if you own a house it makes you a shareholder in the town, which means what's good for the town is also good for you. This makes people of the town work together towards a common goal which is presumably a good thing.