I'm reading the biography of Moses as we speak and the current chapter does paint him as being capable of a unique kind of horribleness, regardless of his other positive qualities.

As one of his friends described him: "He's so forthright and honest that if he saw a man across the street who he thought was a son of a bitch, he would cross the street and call him a son of a bitch, lest by passing him in silence, his silence be misconstrued".