What I'm saying is that's irrelevant to the claim they are making. It is an ad hominem, which is a formal logical fallacy and has been for a very long time (going back well over 2,000 years)[1]. It didn't used to be controversial to say that ad hominem was a fallacy.
Are you disagreeing with me that the above is ad hominem? Or that ad hominem is a fallacy?
Wouldn't it be much better to just refute the claim instead of attack the person's motives? I.e. I think it's pretty damn easy to demonstrate that non white men have been great leaders who have gotten things to work. Refuting that claim is the non-fallacious approach and may actually convince someone honest (likely some third-party who is reading it later, you'll probably never convince the original speaker).