As I said, the Catechism of the Catholic Church calls same-sex attraction disordered and that is enough for me to say that it is not normal and this is coming from someone who does suffer from attraction to the same sex.
That said, I never did like the "If you don't like it, don't buy it." thing. People say this when they want to discourage boycotts and other such things. There is nothing wrong with boycotting a company or a product if one disagrees with the message they are sending. Everyone has a right to buy what they want and to refuse to buy what they choose and everyone also has the freedom to influence others to make a similar decision.
Personally, haven't told anyone not to buy the book because for one thing, it's not even the holiday season and for another, I really don't care all that much about the issue. I care enough to continue on a conversation about it on an online forum but that's about as far as my concern goes.