I agree that he did already evil things, but I think there is a difference between killing members of an alien race for revenge, and slaying human children from your own community.
And I’m no way excusing him, I just think there could have been more nuance to the topic, there are steps of evilness they could have explored to make this more believable.
It’s also very interesting how some people are divided over this scene, e.g. a friend of mine had the exact same explanation as you mentioned, while another friend also found it a bit too much. I guess it’s just subjective, based on your own perception and understanding of “evil”.
My 60+ mother was like that, until I convinced her to stop. Once she ordered a hat, didn’t like it, so tried to send it back. Temu just gave back her money, and told her to keep it. I bet it’s a quality product