Hi scarboroughfair,
.
I'm pretty much the same way. Though, I'm of the opposite opinion...such feelings often do not come from knowing yourself (though they may)...but rather oft times they come from not knowing...or valuing...yourself.
.
As I said, I'm much the same. I would never choose to hurt someone, even if I know they probably deserve it. I have been far too kind to such people in the past. I would never purposely kill someone. If I ever did kill someone...even if by accident...I would have to seriously consider whether I deserved the breath in my own lungs for having taken something so precious and irreplaceable from someone else. I honestly don't know if I could live with myself.
.
Now...it's not a bad thing to be that way. Certainly not for others. But it can be bad for you.
.
Some would consider the above noble. Though, that would mean such feeling arose from some "superiority of mind or character or of ideals or morals." (As Webster would put it) Does this feeling come solely from a deep respect for life and the quality of others' lives? Without recognizing that you are also deserving of the same?
.
Others would say that it comes from fear. Fear of yourself. Of what you're capable of. Of what anyone is capable of. Fear can lead to overreaction. Even a toddler is capable of poking your eye out with a knife. We don't let them play with knives because they don't understand many things, and aren't very good at controlling themselves. Once we have that understanding and have learned control, we don't need to guard ourselves so rigorously. Guarding yourself 24/7 from something...from anything...is exhausting. Not guarding yourself for every little thing though...means that you have to be willing to accept the possibility of mistakes. Having the ability to forgive ones self should something bad happen though, is another issue entirely.
.
For me, parts of the above have been valid at times. Though, it's largely something different. It's very easy to be selfless...when there is no self. Growing up, there wasn't a day that went by that I wasn't told in one way or another "you can't be you." From the snide comments, to the physical beatings, and everything in between. Coupled with a rather harsh paranoid religious culture, withdrawing was really the only defense that I had. Withdrawing from others. Withdrawing from life itself. Even withdrawing within from myself. In order to value yourself on an equal footing with others...you have to be able to see that self in the same light. Otherwise 'selflessness'...doesn't really mean the same thing as 'noble'...it's more literally an absence of self.
.
And while I am loathe to harm others, I have learned over time that some people will take everything that they can from you...draining you dry. Setting boundaries for your own well-being...your own self-respect, self-esteem, self-defense, etc...is necessary. If establishing such boundaries harms someone else...it only means that they were taking too much to begin with...harming you in the process.
.
Religion? Even those who believe in the bible have differing opinions about which translation of that passage is correct...and which different interpretation of either translation is correct. And...heh...you get the idea...I'll stop now before I get flamed.
.
Society? I don't think that society is so rigid regarding expectations of the male populace. (in-so-far as regarding killing and military service) In the military...even for extreme pacifists like us, there is still the choice to be a medic...or some other non-combat role...or even conscientious objection.
.
And despite the above...I still feel much the same way as you. If I had to, if it was the only way to keep me from killing someone else...I probably would kill myself. Knowing myself though...it's unlikely that things would ever get that bad. It's just not in me. It's just not who I am.
.
Someone who feels guilty about flushing spiders...probably doesn't need to worry so much about such extremes.

.
I think I'll take Aisha's suggestion and have some tea.