Most people don't navigate life by moral reasoning for every decision. Psychological research tells us that we'll usually substitute "What is right?" with "What do other people around me do?"
This works pretty well because functional societies have evolved cultural norms that push us towards the most pro-social behaviours. However, what if you live in Putin's Russia or Mohammed bin Salman's Saudi Arabia? Worse still, can we judge the people who participated in the atrocities of Nazi Germany or 1994's Rwanda?
Yes. We can definitely judge. Knowing that killing and torturing innocent people is wrong is a timeless fact that couldn't have eluded the (mostly) men who took part. A second of introspection elucidates this all too clearly - "would I like this if it happened to me?" is a worthy solvent for whether or not you should do something.
Are the actions lawful? I don't care. I could have the entirety of my shambolic Conservative government tell me I'm allowed to steal from my neighbours, and I wouldn't start doing it. Those who follow the law without question are as responsible as those who morally reason by doing what everybody else does - they're not thinking for themselves.