I agree. Unfortunately this will cause some residencies to be slighly less favorable among applicants who are counting on PSLF. A non-profit program (keep in mind many non-profit hospitals are not the ones responsible for attending salaries, so an attending at an academic hospital is often paid by a physicians foundation, but the residents usually paid by the academic center, which is usually non-profit) is going to have one more check mark on the "pro" side relative to a for-profit hospital.
However, one thing to consider is if the hospital is associated with a VA, county hospital, etc., some of the resident's salaries are paid by the VA, county hopsital, etc. So I don't know if it's necessailly a deal-killer if your residency is for-profit. It probably is, but there's a chance it's not. I really don't know how that would work.
It was set up for congressman to help their staffers who earn low pay but all have huge bills w/ ivy league educations which is why the PSLF is discharged tax free but the IBR 20 year repayment is not tax free.