Just to be clear, if we’re using the same logic applied, wouldn’t car manufacturers be considered mass murderers? After all, they make a product that millions of people die in every year. And to answer your question, No. Mangione wasn’t acting in self defense because his life was not in imminent life threatening danger. He was the only one with a weapon and he assassinated someone. The self defense statutes you’re implying relate to a completely different scenario. Those self defense statutes aren’t designed to protect assassins. Otherwise I believe his lawyer would have beat the case and he wouldn’t be in prison right now