Check out lady lawyer's comments, reflect on other similar book deals and think about how behavior changes when money enters the equations. If you do that and you still believe that nothing is motivating the Schindlers save noble altruism, then I've got a pre-owned vehicle (hardly used!) that I'd like to sell you.
Maybe you come from a family that doesn't love their children, but the Schindlers love each other. I know that can be hard to relate to if you have no point of reference in your own life. Maybe it would help if you just examined their past behavior.