1) You seem to be missing the fact that he drew and attacked.
2) It's irrelevant anyway--it doesn't matter if the cop knew it didn't have an edge. Even if it can't cut butter it's still a club and capable of inflicting serious damage.
1) I'm not missing anything. I haven't seen evidence that supports your claim/the cops' claim.
2) A lot of things are capable of inflicting serious damage. Right now I have in my purse several every day items with normal, everyday purposes not related to inflicting harm on anybody or anything which could indeed be used to seriously harm or even kill someone. You probably have at least one item on your desk right now that could be used, easily, to kill someone but most people would just use it to sign a check or jot down a note or maybe scribble a picture.
What is completely relevant is why the cops felt he was a threat. Some guy walking around like any one of hundreds of similarly outfitted attendees at any Comicon should not be seen as a deadly threat.
Police sometimes get things wrong. Sometimes they, like a lot of other people, craft a narrative that makes their mistakes look less bad, and even like the right thing to do.
I have a hard time seeing how shooting an unarmed person in the back, 4 times, is justified.
A few years ago, in my small town, there was a 911 call about a man, reportedly suicidal and probably on drugs, who was on a bridge, threatening to kill himself. In days previous to this day, he had told others that he had a .38 but no one actually saw him with any kind of firearm. In fact, he was never known to have any type of firearm. Friends called because they were worried he would actually commit suicide. He had been in a bad emotional state for some days at that point.
Police were duly dispatched and saw the man, alone, about 35-40 yards away, on a bridge over a river. He had something in his hand, and was pointing it AT HIMSELF, like a gun: to his head, to his heart, in his mouth. One officer observed him from a distance of about 40 yards away through a scope on his rifle. A friend of the man on the bridge approached in a car and attempted to talk to the suicidal man but was ordered away and actually arrested by officers present. Officers demanded that the man on the bridge drop the gun, repeatedly. He did not. Ultimately, the officer with the rifle fired a single shot and killed the man on the bridge. His body was recovered. The object was a small folding knife, with a 3.5 inch blade. He was never in any danger to anyone other than himself. EVER. He never had a gun; no one had ever seen him with a gun; they had only heard him talk of having a gun.
In the pocket of the pants he was wearing was a suicide note. The autopsy showed drugs in his system. He had a history of mental illness but no history of violence towards anyone, nor had he ever threatened anyone at all, except himself.
The cop who killed him was exonerated by the grand jury, although he shot and killed a man who was in no way a danger to anyone aside from himself. There was never any gun. No gun was found on his body, near his body, nor in his residence or in/with any of his belongings. Not one person saw him with a gun, although the police were sure he was armed with a gun the night he was killed.
As an even sadder note, the officer and the man who tried to help his friend on the bridge attended high school together, with one of my kids. The man who was killed was some years younger, but known to the officer (small town) and clearly troubled but with no history of violence.