MacArthur’s command was vast, and he fought the Japanese whose tactics were often futilely suicidal. The Kamikaze planes were an effective, and frightening, tactic. Banzi charges simply spilled blood. In Guadalcanal, Japanese tactics could have hardly have been better chosen to insure the maximum number of Japanese causalities. Still some of the elements of his command must have suffered a better ratio of friendly to unfriendly casualities than others, so at least some of his subordinates would have had to have outshone him in that statistic.
Patton did manage to create or exploit dynamic situations, were the enemy was in retreat, which is the best time to inflict high casualty ratios. He is is probably also credited with casualties caused by Air Force units, attacking German units he faced. When the Germans tried to run on the road in daylight they were sitting ducks.