If I had to make a guess, I'd posit that this is a purely rhetorical claim in order to gain favor with humans here who do favor protecting sentient life as a major goal.

It could be that the desire to cooperation is sincere. In movies the 'bad guy' is usually the one that doesn't just have conflicting preferences with the good guys, but is also psychologically incapable of cooperating effectively to reach the goals. There is no good reason that an agent with preferences as 'evil' Clippy's could not effectively cooperate with humans as effectively as we cooperate with each other.

(Although I agree that even in that case there outbust was heavy on the rhetorical flair!)