I'm not either, however you are wrong.
After WWII the US army carried out a study to find out why so few soldiers put down deadly fire. Long story short, 75% of soldiers were not trying to kill the enemy, turns out most humans don't have a natural predilection towards killing a fellow human.
The study was done by S.L.A.Marshall titled Men Against Fire: The Problem of Battle Command. Marshall recommended small yet highly effective changes to training. By increasing the fire rate along with the other changes hitting the target during combat became an automatic response, before the soldier had time to think.
This could explain the high rates of PTSD we currently see, as people who lack the inclination to kill are killing automatically, by reflex, but afterwards they have to deal with the psychology consequences of having carried out an act that is not part of their nature. That's a hell of an internal conflict.
Go read https://www.amazon.com/Men-Against-Fire-Problem-Command/dp/0806132809
or check out the other studies that world militaries have conducted.
>he startled the military and civilian world in 1947 by announcing that, in an average infantry company, no more than one in four soldiers actually fired their weapons while in contact with the enemy.
Only one in four soldiers actually fired their weapons in combat. Modern military training techniques have gotten that percent much hire sense then.
But the idea that just anyone can be a LitRPG killing machine is pure fantasy
I haven't read this book but it makes the argument that no more than 1 in 4 soldiers actually fired their weapons at the enemy during world war II. https://www.amazon.com/Men-Against-Fire-Problem-Command/dp/0806132809
> Killing is in our nature, religion is a good excuse for it.
I entirely disagree. Killing is not in our nature, it is a learned response conditioned in a community or an individual as a response to extreme stress brought about by the risk of death. Edit: It can have other motivations, but in general cases such as those caused by passion and greed are rare outliers. (The homicide rate in the U.S. for 2008 is 5.4 per 100,000. Source.)
It is not in my nature to kill anyone. It is in my nature to prevent injury to me or those in my "community" (loved ones) and if killing is what must be done to prevent that, then it may come to that. However, killing is usually the last thing to be considered.
Here is a book about the problems encountered in World War II when many troops refused to kill enemy troops, even in combat situations where their lives may have been on the line. It is referenced in this interesting blog post.
> What about primitive tribal people with no (or minimal) religions that managed to do plenty of killing for non religious reasons? What about them?
I am not saying religion is the only cause, only that it is often a motivator and can provide an excuse. Primitive people did not simply kill each other because they wanted to. It is in our nature to survive. Killing for survival is merely a by-product of this instinct.
> If someone is willing to kill for religion, by what measure are they a good person?
It has to do with corrupting a person's natural morality. People who would in general be good can be coerced into committing atrocities given the proper motivation, such as that which can be provided by religion.
Hope that doesn't sound like nonsense. I'm having a bit of trouble organizing my thoughts. Extremely sleep deprived.