There seems to be a confusion of what an MBS is. Mortgage Backed Security is a SECURITY. Its a pool of mortgages that is securitized so it can be traded by investors.
Has nothing to do with the Fed buying property. MBS is a way for banks to get the (illiquid) mortgages off their books and sell to an investment bank, who in turn sell it to investors. The Fed isn't buying MBS to own property, they are buying it to lower lending rates. You don't own any property if you buy MBS you are buying the interest stream. Its a type of bond
http://www.investopedia.com/video/play/what-are-mortgage-backed-securitiesAlso, borrowers aren't in debt because of the Fed. They are in debt simply because they borrowed money. Nobody forces you to borrow money