He meant what he said- that they were "ungrateful snobs and ignorant peasants" and that he identified more with the gargoyles than with them. It's not any deeper than that.
Yes. (Not counting flashbacks, anyway.)
Yes. He was a casualty of war.
4. Why did Duncan become the Hunter?
Greg's answers:
It gave him a psychological edge against his enemies.
[Later, he adds...] He saw the Hunter's Mask as a useful and necessary tool.