Sometimes he just wants to punch altruism in the face. It's such a pain to deal with, and he can't be bothered, so instead of continuing to argue he just doesn't reply. He might do as Sharon says - or at least to some extent, since human civilians would have been his priority anyway - but it's by no means a given.

"Guy's got a point. Lovely though this chat is, miiiight wanna get going before they do something like drop another box of Norse gods on us."