This all started because noted cranky scold Stanley Fish wrote a New York Times piece chiding historians for having opinions about Donald Trump as historians. Here, read Erik Loomis take it apart over at Lawyers, Guns, and Money. Honestly, the original essay makes no coherent argument about why it's not ok to use one's expertise to make arguments and is best dismissed as another example of Fish's mastery of the fine art of concern trolling.
Fish wrote his piece because Ken Burns, the filmmaker and historian, started a Facebook page called Historians on Donald Trump. It presents 21 history professors, mostly via video, assessing Donald Trump. The video currently at the top, by David McCullough, has 2.7 million views. Others have views ranking from around 5K to 500k or so. This is not a minor endeavor. Each post begins by listing the credentials of the interview subject (which is what irked Fish), and they are super impressive. Pulitzer prizes. Best sellers. Distinguished titles at elite universities.
There are only 3 women, one of whom is a Latina (Vicki Lynn Ruiz)*
There is one Latino (Albert Camarillo)*
There is not a single African-American historian (not to mention an Asian-American historian, anyone identifying as a Muslim, or anything else to diversify this collection of scholars).
Ken Burns is a savvy, rich, well-connected image maker. While the profession skews white and male, especially in US presidential history, there are in fact many people with superb credentials at elite universities who are 1) not white men and 2) would be powerful voices speaking against Trump. I hope, if Burns continues this project of lending his platform and expertise to historians seeking to make public comment, he'll diversify.
EDIT: Historian Leah Shopkow pointed me to the "Trump syllabus" at the Chronicle of Higher Ed which a brilliant letter to the editors called, "As white as the man himself." A very analogous situation and, from the letter, links to resources for more diverse comments on the Trump phenomenon.
* Note: I don't know these two historians and am making assumptions about how they identify.