Amazon De-Lists Gay Books As "Adult"

This has to be one of the weirdest and least defensible policy changes imaginable. Mein Kampf is fine. Jackie Collins is fine. But books about gay subjects are now "adult" on Amazon and so not included on best seller lists or rankings. Sure enough, "Virtually Normal" and "Love Undetectable" have been de-listed and stripped of customer sales rankings. Jackie Collins' "Married Lovers" hasn't. My books contain discussions of Aquinas and Freud and Foucault and Burke. I'm puzzled as to why those authors are more "adult" than Collins' adulterous couplings.