Besides the legal issues with discrimination and disparate impact, another important issue here is that jobs that involve making decisions about people tend to be high-status. As a very general tendency, the higher-status a profession is, the more its practitioners are likely to organize in a guild-like way and resist intrusive innovations by outsiders -- especially innovations involving performance metrics that show the current standards of the profession in a bad light, or even worse, those that threaten a change in the way their work is done that might lower its status.

Discussions of such cases in medicine are a regular feature on Overcoming Bias, but it exists in a more or less pronounced form in any other high-status profession too. How much it accounts for the specific cases discussed in the above article is a complex question, but this phenomenon should certainly be considered as a plausible part of the explanation.