[blonde ambition]
That is totally different. In fact, it's incomparable.
When dealing with history, I don't think it's ever appropriate for anyone to censor it. If kids can watch Schindler's List in high school, they should be able to write about an author who wrote a book dealing with the subject of *****, in my opinion.
I would try to convince your teacher to let you write it anyway.
First and foremost, nothing is incomparable. I could compare his problem to a bowl of marbles, if I truly felt like it. However, comparing Lolita to pornography in this instance is a good analogy. Pornography is inappropriate due to an adult nature, and Lolita is inappropriate due to an adult nature. This is public school we're talking about, not a thesis for his Master's.
You are welcome to believe that no one should censor history, but when looking at the school system today, that is an idealistic and unreasonable wish.
EDIT: My opinion in this particular thread has been invalidated. If students are allowed to write about porn stars in school now, then Lolita is acceptable.
And I feel old.