To be very clear, I'm not claiming the practice is just. It isn't. My only claim is that this doesn't arise just because of bias of the interviewers.

If you have racist clients, I'd expect that this would manifest more as assigning the "right" demographic of employee to the clients and keep the "wrong" ones far away from those meetings, as opposed to a straight-up hiring restriction.

I don't think GP was trying to justify the practice, but noting that this exists in domains like finance because the product is an image, not actual performance.