I think it's because in this case they are trying to prove a crime was committed. After all, it's legal to drive into protestors, so if he claims self-defense there isn't clearly a crime, and they therefore would be instigators or fatalities, not victims. The judge is having a really hard time here because no property was damaged, just human lives were violently ended by some miserable sack of dog turds whom I believe should be thrown into the ocean in a burlap sack with a brick in it, so he doesn't know if a crime was committed or not. If he were to accidentally hit someone's tire with a bullet, then the judge would easily be able to tell a crime was committed.