I do believe that there are African Americans who have thick accents. My mom has a thick accent; my relatives have thick accents. But sometimes you have to adjust when you go into the world of film, TV, theatre, in order to make it accessible to people.
I do not think men have more talent. There are a great many women in the arts; novelists, painters, sculptors, poets-but the proportion is far lower in the field of song writing.