I think PTSD or schizophrenia type of disorder that was underlying (something is off def.) prevented them from going in that direction (not practically bc they could have still sentenced him to death). I read where the defendant started the shooting because he thought one of the guys was plotting merely bc he wasn't shooting at a shooting range (Why take a knowingly disturbed man to a shooting range? Very poor judgement on the victims part unfortunately). He then went on to shoot them both due to this paranoid fantasy (what other motive is here).
This just wasn't a coherent crime that justified Murder 1, he obv didn't plan it beforehand. Murder 2 or manslaughter should have been the charge looking at the evidence and the actions before and after the act (he drove to his sisters house who called the police as he waited in his car to later go on a brief police chase. Just no logic to his actions). The guy is dangerous and should be locked up for life, but I think the mental illness in question made it hard to go in that direction. He may have been disturbed before enlisting.