In the face of a truly overwhelming alien invasion, why the hell wouldn't humanity try to surrender or negotiate?
Obviously, survival is an imperative. But if it's militarily clear that fighting back is impossible, wouldn't we at least try, sometimes? In a lot of ways, I'd really like to see a human resistance network movie, rather than a repulse-the-invaders movies if our assumption is that contact always leads to conflict, rather than exploration and dialogue.