Thanks for the tips. If you haven't decided on your three men yet, here are some of my favorites writing on Medium:

John Egelkrout - teacher in my home state of Wisconsin

Walter Rhein - Coincidentally also from Wisconsin!

William Spivey - Wide range of topics but a lot about race

Garrick McFadden - Politics and race

Andrew Ricketts - great writer who shares my first name!

Cory Doctorow - Deep thinker historian