The Black Crowes and Melissa Etheridge were nominated because older industry insiders like them. Ascribing a particular political ideology on someone just because they have a retro rock style seems like a fool's errand. John Mellencamp was pretty leftist for a while until he endorsed Michael Bloomberg, despite being mainly retro rock. Dave Matthews and Steve Earle even more so. Etheridge herself was one of the first lesbian stars and I don't think nominating her would be a successful way to pander to conservatives who are more likely to be homophobic. Black Crowes seem basically non-political. If they were nominating Kid Rock or something, you'd have a point, but the retro rockers they go for like Sheryl Crow, etc... are still liberals who are at least centrists.
I wouldn't always say indiscriminately that country was built for conservatives either. They intentionally began to market themselves that way after 9/11 and it became insufferable, but before that, I'd say most of it was pretty apolitical. There's also the fact that artists usually have broader tastes than their fan bases do. Even Garth Brooks seemed to be pretty centrist at least judging by "We Shall Be Free". Right now, they seem to be going for people who have the most universal popular appeal for the most part, and being an explicitly conservative artist like Kid Rock or Toby Keith usually limits that. It isn't conservative pandering; it's industry insider pandering and obviously industry insiders and record execs are less inclined to like more difficult, alternative artists.
Sadly, I am writing this after Bonnie Tyler had passed away. Bonnie Tyler (Gaynor Hopkins Sullivan) should be included in the Rock and Roll Hall of Fame. She was not just a three-hit wonder from the 1980's like most people think in the US. Unless they followed her very long career, they would understand that she sang and wrote songs that were in many music categories. When I heard that Bonnie was ill, I revisited her catalog of work thinking only of the songs I had known her for. I found that I was very mistaken but came to know how truly talented she was. The way she could control her trademark voice, and how she interpreted songs to connect with people over several generations. Songs from albums I had not seen or heard "Angel of the Morning", "The Rose", "Believe in Me", "Yes, I can"," Louise", and "Eternal Flame" are only a small handful of songs from her extensive catalog of work in a career of more than sixty plus years. I have read she was not only a talented artist but one who was very generous to others in need of help. She never forgot where she came from. The world lost a very talented and caring lady. Bonnie's "Eternal Flame" is shining brightly in heavens beautiful choir. It would have been nice that Bonnie Tyler could have received the honor before she passed away like so many others who deserve to be recognized for their musical contributions. Bonnie was an International Performer not just a couple of hits one time wonder artist from the 70's - 80's in the US. Bonnie should be honored by being inducted in the Rock and Roll Hall of Fame.