The difference between free verse and black verse is free verse has no rhythm. Free verse flows naturally, I guess you can say. It doesn't rhyme. It's kinda like as song. Most songs don't rhyme unless it's rap. So, songs are categorized as free verse while rap is categorized as, well, a rhyme that rhymes.
Reads like a martin luther king or like minded speaker going for freedom of speech and struggle for justice (against the apartheid that Rosa Parks also stood - or in her case literally sat - for). "Mississippi Burning" is a very powerful film.