Hmmm black and gay/lez the same concept Maybe? But their not the same. It could be related if gays wasn't linked with every race.
You see blacks are blacks and can be avoided by a racist of another race while gays can come from any race. So gays are known to be supported over blacks because of that. Back in the days choosing to support blacks was based mostly ones own will when coming from another race but these days supporting gays are more likely because no matter what race you are you could be affected.