Auteme is of the mind that all people are always capable of change, and thus redemption. Killing someone would be cutting that change short, as well as perpetuating the cycle of violence. Even those who have killed others can realize the error in their ways and become better (she has to be at least somewhat flexible, given basically every person she meets has definitely killed people before).
This approach is probably a bit flawed, but kind of matches up with my IRL views on the subject. I probably wouldn't be able to live with myself if I killed someone, even in self defense (granted, how 'defensive' is it to kill another person?); the same applies to Auteme.
She's been picking up more skills to help diffuse situations and end conflict in quick, nonlethal ways. Been a bit lazy, but I'd been planning a teaching thread based around some of the abilities she uses most often to protect others and capture enemies.
I do take a different approach with some of my other peeps. Dorian, who's technically neutral but I'm pushing more light side, is 100% okay with killing people. No hesitation. They threaten him or his friends? They're an active enemy combatant? Six feet under. I very much imagine him like Anakin in the Clone Wars, who has a pretty solid chill vibe until someone he loves is threatened, in which case he's quick to act and takes down those enemies without remorse.
Xeykard (assuming I get him to that point) will probably fall in the middle ground. If he's fully redeemed then he'll be more likely to spare or attempt to convert a dark sider or misguided soul that attacks him, BUT he's also pretty lethal and definitely won't have reservations about more murder when it comes down to it.
I'm of the opinion that Batman should probably kill the Joker. His reasoning of, "I don't want to perpetuate the cycle of violence" is pretty solid in most cases, but I feel it falls apart a bit when there's a bit more repetition. Plus, the Joker definitely doesn't have any family or secret kids that would totally dedicate themselves to fighting crime if he died. Jedi who are more flexible, or those who are actively looking to better those who they come into conflict with, are a bit more compelling to me. (IDK, maybe I just really like Auteme. Or I think Kantian ethics are a bit silly.)