David Dayen summarizes it in a paragraph:

This is just a truism based on the Treasury Department’s own design for HAMP. Every trial modification payment reads as a default to the credit reporting companies. The Treasury Department could have set it up so that didn’t happen; they chose not to intervene in that reality. All of the money between the trial modification and the original payment that borrowers don’t pay during their trial period gets tacked on as part of the unpaid principal balance at the end. The servicers also tack on late fees. Treasury could have banned that. They chose not to intervene. The servicers can proceed with foreclosure operations during the trial period, arguing that the borrower is in default. They can’t actually foreclose (also in some cases they have). But they can go through the legal process. Treasury could have put a stop to that. They didn’t. Borrowers keep getting told they have to miss a payment to be eligible for HAMP. Treasury actually didn’t put that into the design. But they haven’t sanctioned a single servicer for this or any other violation of the program guidelines. They could have done something. They didn’t.

(emphasis mine, though inspired by Big Tent Democrat‘s similar exercise.)

I think that Mr. Dayen is far more forgiving than I am. He implies that it was combination of incompetence and timidity.

I think that it was actual malice. I think that the Treasury Department deliberately chose to deceive homeowners, because they thought that it would give the banks some breathing space.