Humanist Network News has a really interesting article on how Dr. King had the support of a number of non-religious people during the civil rights movement:
Asa Philip Randolph, one of the historical figures portrayed in the exhibit, was instrumental in helping King organize the 1963 March on Washington, along with Bayard Rustin, a pacifist and gay man.
“Most people would have assumed that it was Doctor King,” Jones told HNN during an interview. “The important thing to remember is that Doctor King and A. Philip Randolph worked together in the struggle in the black community. In order for progress to be made, you have to find ways for the secular community to work with the religious community.”
According to [the Black American Free Thought Association], Wilkins, Walter White, James Weldon Johnson and W.E.B. DuBois, founders of the NAACP, all considered themselves agnostic.
With the number of prominent twentieth century African-Americans who were not religious (and there were many), it’s still amazing to me that religion is so prevalent in that community today.