I think it ties to racism. Black men historically have been depicted as “Brutish” and “aggressive” to paint this narrative that they are inferior (black women too but it’s more intensive for men), and has been the basis for law enforcement having more “excuses” to arrest black folks. Over time that’s somewhat evolved to a stereotype of hypermasculinity in black men that people think is present. And when people equate homosexuality with being more “effeminate” those stereotypes don’t mix.