I'm a black former christian, so let me take a whack at it...
If someone tells you a lie long enough, people begin to believe it. Also, the negro spirituals and belief in a 'loving' christian god that would save them got the slaves through harsh times. Like most people who pray right before something good happens, they rejoiced and blamed god for ending slavery, and the religion stuck. Being taught that your former religion is evil and caused you to be slaves in the first place doesn't help either. As for the gay thing: it's about 'manhood' that black men feel the constant need to assert, and black women claim to desire. Lessies aren't a problem, as the men think they can 'convert' them. I've had black men tell me all the time (black women tell me too) that all I need is a man in my life. *eyeroll* I also saw it in high school: The big burly football/basketball jocks were praised by the others, and any male that showed any femininity was shunned or abused, like some of the male choir members I was friends with.