The determination about which books should be restricted from children depends on their level of maturity. A person less mature might misinterpret the meaning of subject matter resulting in inappropriate thoughts, beliefs or behavior. Conversely, a person who is mature enough to comprehend what the author is implying will understand the message being emphasized. Again, parents' supervision is indicated, not banning. Reading is one of our greatest freedoms.
Censorship leads to conformity.
This limits the range and variety of inquiry and expression on which our culture depends. Creativity, research, and technological advances would be limited. Democracy's responsibility is to make available a diversity of views, popular and unpopular. It's not right to coerce the thought of some and inhibit the efforts of others. All community members should have equal access to the entire range of written resources.