1. Germany under Kaiser Wilhelm was an aggressive militarized autocracy that was accelerating an arms race with England and France to gain greater influence and gain colonies/riches
2. The First World War was ostensibly initiated over the Austro-Hungarian/Serbian troubles but somehow included a massive invasion of France and neutral Belgium.
3. Germany added to the "modernity" of those festivities through brutal and repressive policies of the occupied areas (including summary executions) and the introduction of the flamethrower, poison gasses, the bombing of cities/civilian targets from the air, unrestricted submarine warfare (including the unwarned sinking of passenger liners and hospital ships), etc. And I'm sure that I'm leaving some other jewels out.
The German regime was at fault for the majority of the evil of that war - and to a large degree, the "draconian Versailles Treaty" didn't cause the Second World War; it was the continuation of the militaristic/jingoistic culture of Germany.
It doesn't help a bit to look back on those days and see them through misted glasses; all of us had to learn from them and change our cultures and behaviors.
We all might benefit by working on this simple reality "a little'. In the modern era, say the last millenium, the German people lost half their territory to france, Italy , russia, Poland, Czechs in fact every neighbor and its enclaves afield heve been expelled or more likely exterminated. During most of this era there was no hint of German militarism , in fact no German Army, in fact no German nation state. It was actually mostly Mozart.