Might want to check the Black's Law definition of, "Victim." A justifiable homicide is not a criminal act, and therefore in a, "narrow technical sense," it does not produce a victim.
Yes I quibble, but using the term 'victim' (and he may have been using "air scare quotes" when he was speaking) is not in itself proof of mental deficiency.
I also don't think it was inordinate to take a week to reach the prosecutorial decision. Collecting and analyzing the forensic evidence, interviewing the survivors, checking for surveillance footage, canvassing for witnesses, investigating the background and prior history - heck this was lightning speed.
Even the good DA's around here would screw around with this for 18 months. The bad ones (yeah I mean you Zappala) would charge murder and take you to trial and make you convince a jury that you were justified.