ah yes. i see. i was wondering what was at the center of your interest in starting a discussion about URMs in medicine. i understand that you are unhappy with a recent hire who has sub-par performance and who failed to become board certified.
in this light, the URM question is completely irrelevent. in your private practice, it appears that you ended up hiring a dud. it would be different if you were to have a problem with an institutional hiring policy. but in the private practice arena, you pretty much operate under a free-market system, and you have only yourself (and your partners) to blame for hiring this dud. in a sense, caveat emptor. you had the right to request any and all relevent documents (evaluations, board scores, references, etc.) and to have as many interviews as you wanted to judge her performance, and to have enough information to make a informed decision.
there are plenty of bad docs out there. it is not affirmative action's fault for allowing this doc into medicine, but your (and your partners) lack of insight for hiring her. if you are stuck with her, it was also your responsibility to have drawn up a contractual agreement to allow for you to release her without legal reprocussions.
if your partners hired her despite your objections, it appears that your main options are to a) suck it up, b) leave, or c) stage a coups. i like "c".