Don't drink the kool-aid. This isn't about black and white and hasn't been since the story broke. This is about building support to repeal stand your ground laws, which is a vital step in disarming the populace. The plain and simple fact is the police can't help you - they've never been able to. The police are for hunting down and punishing people who have ALREADY committed a crime. Further, over 90% of the crimes they 'solve' are solved due to a witness identifying the criminal.
That being said, are you REALLY comfortable leaving your family without protection of any sort? Is it REALLY going to make you feel better that their killers are punished? Not me - I'd rather they didn't die, thank you. Also, an ARMED citizenry is a POLITE one.