If you think you choose your gender preference you are out of your depth.  No one in his or her right mind would pick to be gay in this world right now.  You are very, very, very sadly mistaken.  And, I know that you know that, because I have yet to meet a so-called 'straight' person who would say, "Yep, I was sitting there at 5 years old, and I said to myself, 'You know what, Steve, I think I'll be straight.  Yep, I think I'll choose to like the opposite gender pool for finding my soul mate.'"  Nope, sorry, it's not a choice.  And that idea has been debunked for decades.  Get over it.  Meanwhile, my understanding is that some Black people resent the equation because it is much harder to pass as white when you are black than to pass as straight when you are gay.  The discrimination is more universally and automatically felt by Black people in a white-dominated world.   The racial stereotypes against African Americans has been, perhaps, more institutionally marginalizing than for gays.