I think the Bible should be in school libraries (and it always has been), but if you're keeping it while removing other books for sex, violence, genocide, pedophilia, rape, homosexuality, or other objectionable things that are also included in the Bible, I think you're being inconsistent and overzealous.
Of course, none of us can completely escape our own biases. That said, librarians aren't airdropped in to small towns from San Francisco; generally, they're local. If they're in a religious conservative community, it's pretty darn likely they are also religious and conservative. They have probably also had some education that helped them understand biases and how to practice avoiding them.
I find your implicit suggestion that there is some underground network of Leftys descending on small town America to become librarians and put LGBTQ books on the shelves laughably unserious. If you want to influence kids, go on tiktok or become a youth pastor or something. It's hard enough to get kids to read books they're actually interested in, you're not gonna get far as a librarian.