So much misinformation as usual.
Anyway, you can't say Islam wasn't beneficial to blacks because it is beneficial to ALL races.
Qur'an 49:13
O mankind, indeed We have created you from male and female and made you peoples and tribes that you may know one another. Indeed, the most noble of you in the sight of Allah is the most righteous of you. Indeed, Allah is Knowing and Acquainted.
Prophet Muhammad's last sermon
O people! Your God is one and your forefather (Adam) is one. An Arab is not better than a non-Arab and a non-Arab is not better than an Arab, and a red (i.e. white tinged with red) person is not better than a black person and a black person is not better than a red person, except in piety.
However, culturally-speaking, of course there have been racial injustices. I'm an Arab (Palestinian/Jordanian) and I fully acknowledge the abhorrent slavery of black people, although it doesn't necessarily relate to my particular people. It was the people of the Arabian Peninsula e.g. Saudi Arabia, Oman, Kuwait etc. and then throughout North and East Africa too.
So this is just to clear any misconceptions about how Islam as a religion has hindered black people. It hasn't. But of course humans are erroneous and corrupt beings and will manipulate ideological structures to exert racial superiority over others. That is unfortunately the reality of the situation.