"The Reader” is a scrupulously tasteful — more on that word tasteful later — film about an erotic affair that turns to love. It is also, more obliquely, about the Holocaust and the generation of Germans who came of age after that catastrophe. This, at any rate, is what the film would have us believe it’s about, though mostly it involves Kate Winslet, her taut belly and limbs gleaming under the caressing light, deflowering a very surprised-looking teenage boy who grows up to become a depressed-looking Ralph Fiennes.