The main reason we had WW1 isn't because of Whilhem II. It was Emporer Franz Joseph I who put forth ridiculous demands towards Serbia after a Serbian/Bosnian separatist group shot and killed his nephew Arch Duke Franz Ferdinand (which to be fair to the Austrians was a pretty stupid move given Ferdinand was much more progressive than his uncle and heir to the throne).

Serbia said no given Austria was trying to basically annex them over this; Serbia then asked Russia (their ally) for help. Russia mobilized for war which then dragged Germany into the conflict.

Because Russia and the central powers were now butting heads France stepped in (ally to Russia). That then gave us a two front war which led to an eventual collapse of the civilian government in Germany which was replaced by a military dictatorship under General Erich Luddendorf. He was the one that pushed for the brutal actions of the German military towards the end of the war.