The difference it makes is that if this was a terrorist attack, then we should consider the SOS position something more than a ceremonial title whose duties are something more than traveling around the world and partying with the locals.
I’ve read that one month prior to the attack the Islamofascists blew a fifteen foot hole in the embassy wall. I think it matters because all involved failed to take any meaningful actions to prevent or defend against another attack. If this were a negligence case against a private defendant the dead and injured would be entitled to punitive damages based on a flagrant disregard for their safety.