I appreciate how you're not talking about "book banning," but something more nuanced, and a deep "why?" Yes.
Another piece of this is an author's POV. I started my writing career with a middle-grade historical novel that would never find a publishing home now. (In fact, I've been shopping around another historical novel for the same age group, and it's not being accepted.)
Here's the thing: it's nigh impossible to get a so-called "quiet" book published for children and teens now. Anything that looks at growing up, developing character and a value-system, will not be accepted. It has to be fantasy or dystopian, and about death and shadowy stuff, etc.
Next year I have my first published novel for adults coming out; I am very close to giving up on writing for young people. And its a shame because it's been an amazing literary world.