Again, not disagreeing with the sentiment, but legally he WASN'T actively killing people. Nobody was in any immediate danger. That means physically and temporally immediate. That means the defences and laws that are relevant are entirely different. That's just how it works and how the law is set up.
Sure but the law includes interpretation by jurors too, and in reality he was an immediate threat. I'm not going to put a man in prison because of a definition that's clearly wrong.
I mean it's true that jury nullification is a thing, but that relates to decisions made in the jury room. Jury vetting is a completely separate matter that takes place before the trial starts proper.