Some choices are non-choices. No one is better than the next with regard to the harm that might come.
But the choice to intervene when you can help? That's a choice that requires serious thought. We can all rise to the occasion when nothing personal is at stake. It's when we or our loved ones, or our interests are in jeopardy by our action, that it becomes a moral decision, no?
Altruism? No such thing. There's always gratification. Even the gratification of assuming that there's no personal gratification. But that's another issue.
Why do movies and books and situations that depict heroic actions move us so? What value do we intuit in those actions? Are we just taught to appreciate sacrifice and honor and courage? Are these real things?
Hitler's Germany operated on a different agenda. Mao's China operated on a different agenda. Both systems had visions of the future and developed moral rubrics around those visions. Within the context of those visions, euthanasia was appropriate, as were many other policies that we find inhuman now.
In today's society, is prolonging life the ultimate goal? At what expense?
I have a vague sense of how I come to moral decisions. I try to be consistent. I try to do the right thing. But we all deceive ourselves, and confirmation bias is strong.
Nietzsche proposed theories. Some were brilliant. Some were, in fact, mind altering. But practically, the path to the Superman was littered with what we'd consider totally immoral actions today. Philosophy is theory. Philosophy is not practice.