By the late 1960s, however, the civil rights movement and rioting in Northern cities highlighted the national scale of racial injustice and overshadowed Griffin’s experiment in the South. Black Like Me, said activist Stokely Carmichael (Kwame Ture), “is an excellent book—for whites.” Griffin agreed; he eventually curtailed his lecturing on the book, finding it “absurd for a white man to presume to speak for black people when they have superlative voices of their own.”
https://www.smithsonianmag.com/arts-culture/black-like-me-50-years-later-74543463/ Here’s an interesting article on that.