BCastle: Elvis's entire dance style and early music style is based on what Black artists were doing for years at the time of his rise. Having two Jewish men write the lyrics to one song doesn't take away from his entire career being built on making that music and dance style more acceptable to young White people. That's the system of the industry, they do it all the time. You can practically follow the trends from one type of music channel to another - Cyrus and Bieber are both quite obvious examples - Bieber particularly has been used to clean up styles made famous by Usher and those similar to him. Their indecent (or in the case of Bieber quite horrible, violent) behaviour has nothing to do with being industry whitewashes. Even dance styles - Harlem Shake, twerking, all decade or more old in their place of origin, suddenly jump into the mainstream. It's practically a conveyor belt. It's not a natural progression or evolution, it's purposefully done by the industry to make money out of particular images, it's a purposeful system.
I am well away of Macklemore's song on white privilege and he can write about it all he wants, he can talk about it all he wants, has he put any of it into action? Has he used any of his concern to boost the actual LGBT+ hip-hop artists, to give them more mainstream airtime? Has he turned down the accolades of being the first hip-hop artist to discuss these issues - no he hasn't, no he isn't. Nothing wrong with liking someone problematic, but he is. Any talent or recognition of the problem doesn't help if he doesn't do anything with it. He is not a credible voice for the LGBT+ community - because he isn't a part of the LGBT*+ community. Just like Lady Gaga who has been promoted in the same fashion, regardless of complaints from the actual community about her horrible treatment and shouting over us.
Most mainstream rap is produced or at least makes its money through the white music industry, it has a function within the industry, it has to portray a certain image. You'd need to get beyond those to see artists without that imagery, hence why you haven't seen the LGBT*+ hip hop artists before. A lot of rock and pop has problematic lyrics or imagery as well - Axl Rose has a song full of n words and homophobic slurs and goes on about being "pro-hetero", many of particularly harder rock genre are full of it, no one complains that all rock has a homophobia or racism problem. Pretty easy to guess why.
Rhianna's songs are her processing the complicated emotions around her relationships. Taylor Swift does the exact same thing. One is torn apart, the other it's a nudge nudge wink wink joke. One having more difficult relationship is not the defining factor. It is well known Pink has also had rough relationships as has Madonna. Her abusive relationship with Sean Penn certainly didn't have the same effect and that involved a baseball bat and still confessing to loving him many months after.
A lot of this has already been written about and more detailed sources written by people within relative communities who choose to discuss or educate others and can be through whichever search engine you prefer to educate yourself with if interested.