I honestly expected the mob to be connected to Sumire's death - but in the end she would have died regardless. So aside of being morons in general, their fault was that Johann could not get to her quick enough, or... ?
Honestly, not quite what I was expecting as the source of Johann's hatred. It's like he's not even pissed about the injustice towards oracle holders, but he's simply mourning the loss of a loved one he could do nothing to save.