Even if we grant that the German Empire was more cruel in waging war, which I am by no means prepared to do, the war did not take place in a vacuum. If the purpose of America entering the war was to make the world safe for equality, freedom, and democracy, then the conduct of the belligerents outside of the war is totally fair game. To that point, I'm sure I don't have to remind you how Great Britain had been treating its colonies for hundreds of years.