DL is another way of saying "closet case". As such, there is nothing specifically Black about it, as closet cases are lying pieces of shit irrespective of their race, ethnicity or gender. Are there added pressures to conform to a mythic standard of masculinity on the part of men of color? Of course! But it's internally driven in part because being gay or bisexual is seen as a white thing, somehow, within communities of color. There's little if anything I as a middle-aged white guy can do to change that.
What I can do is encourage anyone who wants to broaden his/her sexual horizons to actually do so, openly and with pride not only in one's self but with confidence that the acts themselves are healthy and positive expressions of his/her innate sexuality; anything less just pushes folks back into the immoral, self-loathing closet of fear and regret.
FWIW, the rise in HIV infections within the African American community is actually rather complicated. Although the majority of new infections occur through unprotected bisexual contact, there is a large percentage (upwards of 30%) that occur through IV drug use and the sharing of works (needles, etc) and involve no homo/bisexual sexual contact whatsoever. There are many issues involved here and cannot be ascribed entirely to risky sex.