I don't think Gregory had any ethics. All he seemed to want to do was further his position no matter the cost, not even at the cost of human life.
As for Lamar, I haven't watched 1840 in a while, so I'm really not sure what's going on with him in that scene. And as Magnus mentioned the WP hasn't got up to that ep yet. But I suspect that when it does this topic will be revisited.