Does this superhero/villain motive work?

As someone who has lived through trauma it is always refreshing to encounter authors who consider their antagonists are made by their freewill reactions to life and not determined by biology or having survived a bad childhood. Too many authors are too lazy to try to create a motive or goal beyond prejudiced determinism, and nothing is as boring or stigmatizing as a bad guy who is the bad guy because the author said so without imagining the character had anything like freewill. I feel like a mere obvious plot device is attacking the hero when there is no freewill or soul inside the antagonist, and then I sit and wonder how many people I'll have to meet who consider me lacking my own soul purely due to ignorant fear-mongering by which is perpetuated the promotion of biased ideologies such as moral eugenics(now genetics) or the caste of surviving tragedy. There are many people in real life who take divergent reactions to the same tragedies, war is perhaps the best recognized example, but though less talked about, it's more common to happen in regards domestic violence.

https://www.youtube.com/watch?v=htRzFBHWOqQ

https://www.youtube.com/watch?v=J3DcedvkzJY

It could work as a catalyst, but I think it would take more than a single event to make the one brother believe ALL humans are evil. It might be more believable to describe the murder of their mother as the first link in a chain of events that end up with each of them being at opposite ends of the spectrum.

Yes, it's fine, and it's a tried-and-true technique. It can be wonderful.

Yes, it is just the type of cliche found in comic books.

It makes sense to me.