Because this is a boil-the-frog situation. The path is k-12 school libraries -> public libraries -> academic libraries and bookstores. The way fascists get the public comfortable with the idea of banning books is by starting with examples that look like "common sense" to the uninformed, and then ramp up the attacks as they gain institutional power.
While attempts to ban books from stores are currently few and far between, one notable example was this attempt to get Gender Queer removed from the shelves of bookstores in Virginia: https://www.washingtonpost.com/education/2022/05/20/gender-queer-barnes-and-noble/
The person who pointed out that it's about power has it in one, but if you'd like to learn more about war rape's use in modern conflicts, Our Bodies Their Battlefield: What War Does to Women by Christina Lamb is an excellent introduction. Despite the title, it does touch on male rape as well, and it gives a comprehensive overview of the ways rape is used as a weapon, as well as the ways survivors recover from it.
(Note: I wish there were more research on the subject for laypeople, focusing on the use of war rape with men, since it shows up throughout conflicts as well - but Lamb's book was a first. It's a very recent title, and my hope is that other brave writers will put together more books on the subject.)