What you said is true but irrelevant to the minds of many American blacks. All they know was that all the whites who had owned them and discriminated against them in America were Christians.
Which leads to the speculation that if American whites had been Muslims or some other non-Christian religion, angry blacks wishing to foil whites would have become Christians.
I think Elijah Muhammad, Malcolm X, and similar black malcontents chose Islam as a way to spite Evil Whitey rather than a strong belief in Allah and the Koran.
And look at the fake holiday of Kwanzaa created by Ron Karenga to try and usurp Christmas as the holiday for blacks.
A lot of the wacky things black people do they do to spite whitey. Look at the weird names black American mothers give their children. I worked with a Kenyan immigrant who was a Christian. She and her family members had regular Christian first names. No weird names for them.
In the quest for "non-white" traditions, some have been adopted, some generated out of whole cloth.
Kwanzaa is a fine example.
I think you are right in that traditions were egregiously sought which were NOT "white", as if seeking identity by defining themselves as what they were not, but in doing so discarded a number of things which were inherent in their culture in common with European culture--things basic to cultural survival.
Names once had meaning. Even traditional African names mean something.
I worked with an African whose name meant 'Cause for celebration'.
Amongst those who follow the teachings of The Bible (or Torah), names have meaning.
In Hebrew, my first name means "May Yehova give increase", a prayer.
Unlike "Le-a" (pronounced "Ledasha", which may have a meaning I am unaware of), the biblical and even other non-biblical names meant something.
Iron bars do not a prison make.
Some people will wear their hatred like the chains Arab and other African slavers put on their ancestors, and never realize that those chains of hate hold them down more than any person or group today.