“In your ‘what if’ scenario, the suspect kills a cop which means he would have no problem killing some random security guard. A citizen has no obligation to intervene in a major felony involving a weapon.”
Indeed, no obligation, but if he decides to act and bravely takes that risk he is a good man willing to take risks for the protection of others. That sort of character is too often beat out of young men. Being a sheep-dog is no longer allowed (hence his firing), but being a sheep is.
I blame lawyers and SJW.
It’s absolutely lawyers! If you take actions against a perp, you will be sued by the perp if your actions produce an injury to the criminal. Everything always leads back to lawyers. Sure, there are some good ones out there, but the bad ones sure make it difficult to respect the profession.