They wont allow minors to take out porn. Simply, they wont and it would be illegal for them.
What is adult content? A cartoon butt? A book on breastfeeding? "I can't define porn, but I know it when I see it" has led to Calvin and Hobbs being banned.
And second, underaged kids can not checkout non kid material without adult in the loop. That part is simply not true, the librarian will say no to the child or ask for parents permission.
If your goal is "prevent children from accessing adult material", it really isn't that limited.
> underaged kids can not checkout non kid material without adult in the loop
They don't need to. They can read it in the library; that's what libraries are for.
And obviously "adult material" is not referencing cookbooks for housewifes nor antic philosophy nor fantasy books meant for adults.
It does in fact means porn and such.
Or is it the pearl clutching where a novel with a same-sex kiss is smut? What about all of the graphic acts that happen in the Bible?
And yes, there was considerable pearl clutching over same sex kiss. To the point the supposed old school bastions of freedom would not print it, would not put it in the library and would do everything possible for kid not to read it.
The physical world of back then was considerably more restrictive in terms of what kids could access. Whether in the libraries or outside of them.