From the stuff I learned over the years it was a "we don't always agree but he's my guy" type of deal.
A quote I found from Jesse Jackson when Castro died:
“He was a hero in Africa, Latin America, and North America for those who needed freedom from oligarchic and autocratic oppression,” the Rev. Jesse Jackson said of Castro in a statement about the Cuban leader’s death. “While Castro, unfortunately, denied many political freedoms, he at the same time did establish many economic freedoms — education and health care. He changed the world. While we may not agree with all of Castro’s actions, we can accept his lesson that where there is oppression there must be resistance.”
Then you have the most well known cases of Malcolm X and Mandela giving him huge praise. If there was one thing very clear about castro, it was that he was not down with white supremacy's grasp on people of color at all.