This was the one part of the episode I didn't like. I felt like "Mr Thoughtcrime" who is going for diplomacy would try a bit harder to justify his position.
Something as simple as "If I knew, with 100% certainty, that the child next to me would become the next hitler. That a million people, and there million children, would die and suffer horribly at his hands....wouldn't it be murder not to stop him when I could?".... something like that. Keep in mind, several modern legal systems have tenants that if you have foreknowledge of a crime, and do nothing about it, you can have some liability. Imagine if you actually could know with 100% certainty someone was going to commit an unspeakable crime....it could be argued you are morally and even legally compelled to stop them. Whether you want to buy that argument or not, at least give it the old college try.
That said, I'm definately digging Ethan Hawke's character. He is both smooth and creepy, and the "former avatar" angle adds a lot of neat context between him and Steven/Marc. Also, a hell yeah to Lela, best sidekick we have had in a bit, comes in, kicks ass, stays loyal even though she really has reasons to leave, even tries to respond to "Steven" even though she probably thinks its a lie....yeah she's pretty cool so far.