I've noticed that most Lightskinned brothers I know preferred Darkskinned women. The lighter the brother, the darker the women they seemed to go after. Example, the last two weddings I went to, my little sister's and cousin's, the brides are Darkskinned and the grooms are Lightskinned. Across the street from me, the brother, who is light, is married to a sister who is dark. My maternal grandfather is light with green eyes, my maternal grandmother is dark with black pearls for eyes. So on and so forth.
The above is all only anacdotel evidence, though your assertion has no real evidence backing it either. Out here in the world, I see Black people of all skintones with each other, marrying each other, and having children with each other. Just like you see some Blackmen out here lusting after non-Black women, you can easily see the same with some Blackwomen too.
So no, it is not common knowledge that most Black men prefer LS women. Just because the grifter Umar Johnson says that and the entertainer class has made that their preference, does not mean that is the case for most Black men.