Grant turned the handle of the meat grinder because he had more meat than Lee. Grant was a butcher.
No more so than Lee sending his troops up Malvern Hill or Cemetery Ridge.
Lee lost a higher percentage of his men in battle than Grant and his losses in the 7 days battle were an astronomical meat grinder. He let his men get chewed up because he figured McClellen was timid and didn't have the stomach for such battles - and he was right.