This is the context - an Idaho law that penalizes any library that allows minors access to "inappropriate" content, and lets each child's parent define what "inappropriate" means. So libraries could be penalized if, for example, a homeschooled Christian child reads a book on biology that mentions evolution or a YA novel with a gay character, and their parents object to it. Or if a liberal parent objects to their child reading the Bible or Quran.
Given the wide scope and uncertain limits of this law, some Idaho libraries are banning minors entirely. As was, I suspect, the goal.
Laws like this are becoming widespread in red states and will likely become federal law with Project 2025.
The United States is becoming a nation where parents' right to keep their kids stupid and bigoted is more important than children's right to learn. And if that isn't a sign of collapse I don't know what is.
California has some good rules on the book about this: https://www.scu.edu/library/policies/confidentiality/
AFAIK this applies to minors with a card, too. I have heard that in my city when a librarian gives a minor (I think over age 13?) a card, they make a point of saying, "we will never tell your parents what books you check out" (or something like thay). Obviously federal law trumps this (looking at you, Patriot Act...) but there are some places in this country sorta doing the right thing, which is heartening!