Not commenting on the legitimacy of this, because it's hearsay. But I think that it demonstrates a lot of the AMC hate, not all of it, is misplaced and should be directed toward the IMBs.
IMBs do not care about appraisal quality, even when they are direct engagement. It is a simple math equation. They make more money with churn and burn appraisals than they lose in collateral repurchases. Meanwhile, portfolio lenders, some of which operate as direct engagement, some of which use AMCs, and some of which do both, tend to care more about the collateral risk and are willing to pay for competency as long as it's staying on their books. Some portfolio lenders have a direct engagement panel for the in-house loans, but then use Fast-N-Cheap AMC when they are selling to Fannie and Freddie. It's not about ethics or doing what's right, it about being able to control outcomes to improve the bottom line.
It cannot be said enough.