Like I said, I'm not a hunter and I've never been a hunter, thus I know my answer is not as precise as possible and I don't want to attempt to answer too deeply without proper reflection. However, I've listened to hunters before and the point is that I don't accept that they are mindless in their hunting and yes their killing. Like it or not, killing is a part of life, it is necessary. You seem to be confusing that with some morality construct created by humans. Nature doesn't teach us morality.
I know with a quick look that hunting can seem like it's all about killing, but if that were the case than why go thru the trouble of the hunt? Why don't you try reading thru here and with an open mind try and understand what attracts hunters to the hunt.
http://homestudy.ihea.com/abouthunting/01why.htm
You want to talk about people that enjoy killing, than you need to talk about serial killers, who interestingly enough start out with killing animals (not hunting), but soon advance to humans. Now that mindset is very confusing to me.
Like it or not we are animals. Even if you think we're some type of spiritual entity, than we're spirits that inhabit an animal's body and we must bow to certain animalistic tendencies. We fit very nicely into the Kingdom of Life and that's why we still use animals for medical experiments.