I think that depends a lot on the age of the child in question. I absolutely would simply forbid an 8 year old from entering a library or book store with neo nazi writings or aum shinrikyo literature or Ted Kaczynki’s manifesto easily accessible. Trying to provide appropriate context for everything at that age is simply not feasible.
-- You have treated the «8 year old» as a newborn without previous protective formation - so a sad case already;
-- You have defended barring access to all decent libraries and bookstores - which in their hundreds of thousands of volumes do have lots of trash and biased texts. They also contain the good ones.