Originally Posted by Farren
I think he cared about his Dad. It was just that in the case of his mother he literally saw her shot in front of him, and shot because he couldn't perform the way Shaw wanted him to. I could see how something like that was a lot more traumatic for him. Also, it gave him a more concrete person to seek revenge on: to be able to point the finger at Shaw and say "You're the one who pulled the trigger, and you did it purely for your own reasons" is a lot easier than sifting through the murkiness of responsibility of the Nazi bureaucracy -- especially when you're executing your own justice.
Besides, for all we know, Erik did go after other Nazis at the camp his parents were in.
True, he did have a wall full of Nazi's that he had hunted down and killed.