I believe your questions have been answered. The fact of the matter is, as TS pointed out, something immoral can be found in almost all works of fiction. Will you prohibit your child from reading all fiction? What about the newspaper? Immorality abounds in the news also? As for the pedaphelia book or sexual fantasy book, there is a difference. HP is a children's book, these others would never be considered children's books, therefore no parent in their right mind would read said books with their children. I have no problem with using fiction as form of entertainment. I do not use fiction to teach my children spiritual doctrine, for that there is the Bible. Fiction is a way for them to sharpen their imagination, the bible is a way for them to grow spiritually. For that matter, I do not even allow my son to read HP, at least at this point in time. He has an active imagination, and is a writer of sorts, himself. He is an avid reader who tends to create stories that resemble some aspects of the books he reads.
We talk about this all the time, and I feel that until he is a little more mature, (he is nine), and he has a better grasp at his own stories and characters, he cannot read HP. I, however, find no fault with parents who do allow their children to read HP, as each parent knows what is best for their child. I'm glad you have strong convictions, and you are holding fast to them, but do not place your convictions on others. As John of Japan stated earlier, we need to have discernment in the choice of books we read, or allow our children to read. Just because someone's convictions are different then yours does not mean they are not convicted, or are avoiding the truth.