Not true. One of my friends is doing IBR on a salary of about 60k and ~250k in loans and just bought a house with 150k mortgage. They do NOT count student loans for mortgage applications except for your *monthly* debt to income ratio. In this way, IBR actually will end up helping me or other people afford houses.
Total debt and total available credit is 30% of your FICO score, which will impact your rates on mortgages (FICO being the actual credit score used to determine your interest rates).
It's just a tidbit to keep in mind as a higher rate means you pay much more over the course of the loan for the same house than somebody with a lower interest rate. I don't think IBR is a bad thing, but it may not always be in the borrower's best interest.
(source: http://www.bills.com/fico-score-calculation/)