There isn't anyone else.

[There aren't enough humans left - Michael doesn't have anyone left who isn't Dean.]

No, I'm not happy. We tried to spare the planet and you fought us.

[He can see that, and it hurts on a different level. Raphael is one of the few angels who does, in fact, love humanity. And wants them safe, not suffering. He just disagrees as to how to accomplish that.]

I didn't want this. For the planet, or the humans, or us.