First of all, Dr. Seuss's political cartoons were not "pro-war." They advocated that America should go to war to stop Hitler, and they mocked isolationists, but that's only because WWII was one of the only fully justified wars in history. Even pacifists like Albert Einstein were swayed.
Dr. Seuss was actually a staunch liberal whose cartoons and children's books warned about the follies of militarism. (Example: his book "The Butter Battle.") It is true that his cartoons in the 1940s contain racist depictions of Japanese (and furthermore, some of his earlier cartoons contained racist depictions of blacks and Jews, though he later became a staunch advocate of civil rights and critic of anti-Semitism), but that only shows that he was a man of his time, when anti-Japanese hysteria was so extreme it led one of history's most liberal presidents, FDR, to place Japanese-Americans in internment camps. Like FDR, Seuss wasn't perfect but did have many genuinely progressive beliefs.