When you say ” beating a child to death just because he can” you have concocted a scenario in which the passerby has perfect information, right down to the motive. It would seem clear in such a case that ignoring this situation would be morally reprehensible. Ethical duty, lets change the scenario. You are walking by when you see not one but three men beating a child(outcome unclear), you are not sure of the motive, they are heavily armed, they are police. What does sheyboer do, no, really what do you do? Do you have an ethical duty to make a widow of your wife and deprive your children of a father? You can’t be sure of how this situation unfolds, maybe you become labeled a cop killer, maybe a martyr. Maybe as a martyr you encourage other people to stand up to corrupt cops, maybe this turns into a war between police and civilians.
Governments use people to murder and oppress other people. Take two groups of people, oppressor and oppressed, put the oppressed in power, the outcome is not harmony. Whatever the truth behind a war they are all couched in terms of humanitarian. There is no such thing as a humanitarian war. You are talking about a large group of people who are lied to by a small group of people, convinced they are duty bound or otherwise fighting some perceived injustice, being murdered by another large group of people who have been lied to. As far as I know Hitler never gave a speech to his masses where he stated “my fellow Germans we are a bunch of sick effers, are you with me!”.
What is a preemptive attack? Striking a flotilla amassing at your border is a defensive act. Bombing a country for making threats of war is preemptive. Killing foreign civilians is not humanitarian. If the US put an end to Israeli oppression of Palastinians , how do you think the remaining Jews fare in the aftermath?
Oddly enough, I think I could concoct a scenario for a just war but it would not be humanitarian. Thanks for the post, interesting topic to think about.