I have always been against the banning of books in schools, and it is an issue I feel very passionately about. I am 23, so take this from someone who recently went to public school, and who experienced many of the struggles that went on there:

By banning these books, you are creating a fear in these children. You are teaching them that they should be afraid of depression and anxiety and sexualisation. What will they do, then, when they have a friend who admits to feeling suicidal? What will they do when they themselves feel anxious and depressed? 

Teach your children that while the world can be terrible and scary, it can also be lovely and honest and beautiful. Teach them to read, and help them understand perspectives other than their own. Teach them to nurture and love and help others. Help them and their friends understand that they are not alone in what they are feeling and experiencing. Teach them not to fear, but to have a healthy awareness and understanding of these issues. Reading these books can help them understand that. And that is a beautiful gift that we should cherish instead of destroy. 

It is never too late to open your mind to new possibilities.