It's also hard to say that you've "killed" someone if you had zero physical involvement in somebody's death. But I guess words are very flexible these days.
> Where did you get the notion you need to be pulling the trigger to be morally responsible for someone's death?
"Where" is a weird question since I didn't get that notion in the first place. But "being morally responsible for somebody's death" is a vastly more nebulous notion than homicide.