It is indeed ironic, but the losers always get the blame and when one of the losers is left "standing", all the blame seems to go his/her way.
However, it is worse for William. He actually did not push for Austria's demands on Serbia. W wanted Serbia to be punished, but everyone, including William felt the ulitmatums were too extensive for any country to submit to. William tried, in fact, to get FJ to lessen the demands, but to no avail. What William did do in response, was to get Serbia to agree, thereby avoiding a war. It is a famous quote by William, "We have achieved a moral victory (and war is avoided)". The Serbian crisis was smoothed over, but when Russia mobizied troops on the Serb border and France responded by supporting Russia, Germany followed with a so-called "defensive" troop placement at the French border....but had to walk across Belgium! The Belgium territorial breach gave England a reason to declare war. A total mess among nations who were like pressure cookers without the steam release regulator working well. In spite of what was the power of the monarchies, by 1914 the real power in capital, industrial giants, and war technology created WWI. I think there was little Willie or Nicky or Franz Joseph could do to actually cause or stop the war.