Why? You're buying the insurance to protect the lender, anyway - so the money's for their benefit, wherever it ultimately goes. I think it's fine for them to choose whether they want to purchase the insurance or self-insure; it's no skin off the borrower's nose.
Except for the fact that you are paying for it, and they said you HAD to buy it, it costs this much and it has to come from our nominated LMI company, then pocket the money.
That's fraud.
Edit: I doubt that they do as above anyway, as BV said i'm sure they cover themselves, i'm sure that the Insurance company simply throws them a nice party with some of their profits, this happens in many businesses.