I read that myself, and was a little shocked. I assumed I picked him up wrong.
I assume he meant strict definition of anathema rather than homosexuality, and that gay sex is something that the aversge straight person would despise doing. I would despise being screwed in the ass by a man, or a woman with a strap on, therefore anal sex is anathema to me. Doesnt mean that its wrong for people who like it though.
I hope thats what he meant anyway.