There are few things more disturbing than to find, in somebody we detest, a moral quality which seems to us demonstrably superior to anything we ourselves possess. It augurs not merely an unfairness on the part of creation, but a lack of artistic judgment. Sainthood is acceptable only in saints.
We demand that people should be true to the pictures we have of them, no matter how repulsive those pictures may be: we prefer the true portrait in all its homogeneity, to one with a detail added which refuses to fit in.
You slam a politician, you make out he's the devil, with horns and hoofs. But his wife loves him, and so did all his mistresses.