I have discussed censorship and banned books previously on this site. However, I will give a short summary of my opinion. I believe that it is the job of the parent or guardian to decide what material their child reads. It is not their place or business what other children read.
I know of many books that I would not want my children to read and I will be in charge of ensuring that they do not get those materials. I do not support anyone else telling my child what to read.
It is the same with books that my nieces and nephews read. It is to my place to allow them or disallow them access to certain books. If I really feel strongly about it, I will discuss it with their parents.