...when a person says they would refuse to shoot someone threatening their life?
Here's the next headline news story about "nice guy shot by killer...wife stunned". If someone is truely a pacifist and it shows in their life all the time, and would rather die than take a life, I can actually respect that.
But most of the people with the "I can't take a life..." line are scantmonious, self-rightous, pretentous ass-clowns. They drop that gibberish in an attempt to appear smarter than other people in the room or somehow attempt to make you feal bad.
They WILL be the victim someday and assuming they survive they'll be scratching their heads wondering "why, why did this happen to me". They'll be stunned to learn criminals are not impressed with how smart they think they are. It will really fry their noodles to learn criminals actually prey on them. Then they'll want to ban guns and take profits away from oil companies to make themselves feal like less of a loser.
But there's another type of "I could never take a life..." person. And that's the guy who buys a gun, fires it 5 or 6 times and tosses it in his nightstand. He treats it like a magic sheild that will protect him from his family. He never practices with it. Never takes a training class. Never does walk-thoughs of his home to pre-plan how he will clear it. Never dry-fires. Never practices trigger controll. Never practices malfunction drills. Just thinks because "he has a gun" he's now ready. He may talk about shooting the gun but he wouldn't know condition one from tap-rack-access.
He hasn't said it outloud, but he's clearly stating that he *very likely* not take a life because he will freeze and the bad-guy will take it from him before he can figure out what to do.