This is going to begin with a very strong controversy. I'm of the belief that ethics are derived from objectives and relative practicality for accomplishing said objectives. To put it simply: Nobody aims to miss their mark, because even an attempt to miss is an attempt to fulfill a goal.
If we start from there, it's very simple to forgive almost anyone for anything. Just try to think about anyone like you're an author, that they're a character you're writing who has a clear motivation. Some characters have motivations that will always clash with the motivations of other characters, depending on how effective each of them are at fulfilling their visions. Every villain thinks they're doing something good, and all that makes a villain is a readership that has motivations that render the character's existence as an impractical factor for fulfilling the readership's desires. A very common example involves, say, a target demographic of parents who pay for movie tickets having an intrinsic motivation for not having to think about children being hurt. That target demographic sees a character who threatens to harm children in the movie and suddenly that whole collective of viewership has an obstacle for fulfilling their own desires. Upon seeing a character who might be practical for fulfilling the desires of the audience, rising against the character threatening to harm children, that character is then made a hero. To show you how flimsy our brains are with this stuff, imagine for me a movie with a trolley problem between the survival of a small group of children and the survival of humanity. The character who sacrifices the rest of humanity to save a small group of children is going to be sympathetic, heroic even, despite killing more people than Hitler.
But the thing is, that movie with the trolley problem would only work on someone borne of a culture that values children virtually above all else. Someone who isn't motivated to care about whether or not a child lives or dies would be the person you would want in the pilot seat in that situation if you personally value society, your family, living to see the next day, more than a group of children you have zero relation to. When I phrase it emphasizing the children aspect of this, it seems difficult... but imagine how many more children are within the entirety of humanity. I say children, and I activate a pleasure center within your brain. You want your fix, you want to keep having your fix, so if I threaten to take it away I'm suddenly a villain until I give you a suitable substitute. The other children were always there, I never said they weren't, but when you hear 'humanity' you get a different buzz than 'children'... and that's just how the cookie crumbles. You like getting high, I like getting high. My advice is that you pay attention to what you're doing, so that you can control it.