Interesting you should say that. I have been repeatedly hired (usually by black men) to edit their work. It is often because of the vernacular issue as well as looking out for the underlying message. I am the comma police who despises overuse of exclamation points. Usually once we get that battle out of the way, the rest is a breeze.
My toughest assignment (in this regard) was an author (black male) who wanted to write an entire book about why black women should be respected. He had such superb research on black women I did and did not know. The problem was he just kept making snarky, hostile comments toward white people the entire time. I finally just had to have a heart-to-heart with him to ask, “Is your goal for us to learn about black women? Or, is it to complain about white people? Because the complaints are getting in the way of the best part of your book.”
We finally reached a middle ground, where he could complain when it was significant to the woman he was talking about (ex. a historical person who was stopped from doing _________ because ___________ was racist). At the time, I just wanted to edit the book. In retrospect though, I just have this feeling that had he not purposely looked for a black woman to edit his book about black women, he would not have received my critique well. He wouldn’t have taken it as constructive criticism. So from that standpoint, yeah, I can understand why people want to pick and choose their editors.
It would not be fair for me to point out that I would not be the editor that I am right now without the help of one white female editor in particular, who was patient enough to help me learn all the things that school did not teach me. But I went from working with her to a sista who absolutely had no idea what she was doing and was just hired by a friend. Be careful that you look for an editor who is qualified and not just black. I have worked with a lot of outstanding African-American journalists, writers and editors over the years. But I’ve also worked with at least two who were just bad at their jobs.