Mr. J., you are quite right about the legal aspect. What I was thinking, though, is that with enough kinkiness there may easily be other problems, including other criminal acts than the sexual act itself.
But assuming our necrophiliac has followed the letter of the law in most aspects of his life, would I be able to be objective with him because of his sexual activities? Could I keep my own repulsion from influencing my thinking in a negative way. The obvious truth is, I don't know before I have tried. But damned if I didn't try!
Assume you have a really good relationship with a sadomasochist (sexual issues not being the presenting problem but coming up later). The person's views of life are different from yours, but you are comfortable with them. What I would very much like to understand is then why exactly would it be too difficult for you to be able to help this "whipper"/"whippee" in the sexual area?
What I'm aiming at is why do we consider sex so special? If you were a fanatic vegetarian, I wouldn't think it would be very difficult for you to help somebody who is not. A bloody steak may be repulsive to you, but you probably wouldn't be shocked about it. Sex is as normal and common in our lives as eating. (If eating is too mild for you, think of some yucky, wacky obsessions a client might have. You would be more likely to be able to suppress your repulsion there, too.) Why do we expect everybody to have sex in our way when we don't expect everybody to eat our way? Both are bodily pleasure-seeking activities where chemistry is heavily involved.