I think there is a psychological reason behind this why this is happening, because most black Americans come from christian families. Unfortunately black Americans have been unequally treated and this is still happening, sometimes in the name of Christianity.
I know that many black Americans have struggled with the feeling of being accepted by the Christian God, because many times what they have heard was: "God doesn't love darkies", "All blacks will go to hell", "Blacks are cursed and won't get the same reward in heaven like whites". Even in churches they sometimes have been badly treated. And I believe that this is the cause that black Americans seek their refuge in the Islam, because they think the Christian God is a white god who doesn't love them and the God of the Islam is coloured and let's be honest: Christianity has been extremely "whitened", like Jesus painted as European, biblical characters are always played by white people in movies, etc. etc.
The truth is: this is a trick from satan to keep you away from the truth and lure you all into darkness, Jesus is the only way to heaven, not otherwise. Wow, the devil is a great deceiver and he uses frustration, pain, you name it, so that you will refuse the true love of God. Don't fall for it: Islam is a lie from satan. All the people who have died in the name of Islam know this already and I am sure they would warn you if they could, but it is too late for them.
God loves everyone and never will judge you by your skin colour, wealth or status but by your heart. But you can only have salvation through Jesus Christ.
Watch this amazing video from a woman who has been in Hades and then she realized it was because she didn't accept Christ in her life, but by a great miracle, God has delivered her from that place.