they investigated a man parading around town displaying a deadly weapon....
No, they didn't. What they "investigated" was a law abiding citizen who was going about his normal business wearing a well secured firearm in a holster. There is a huge difference.
The word investigated is in quotes, because I think what they did was harass the individual. Investigate would be to arrive on the scene, observe a law abiding citizen legally carry a firearm in a holster, say to themselves, "Well, it's in a holster, he is not committing any crime in our presence, we do not have any report of him actually committing a crime, let alone one involving a firearm, therefore without reasonable suspicion it is illegal for us to ask him for ID, so there isn't anything we can legally do, let's go back to the donut shop."
The absolute most that the cops could have done legally would be to ask him his name so they could check for prohibiting factors against firearms ownership, but, even then, they could not legally detain him because they had no reasonable suspicion of any crime having been commited nor any crime commited in their presence.
Someone - anyone - please explain how the police are supposed to tell the difference, on sight, between "innocent citizens who are breaking no law" and criminals.
I don't understand your point, DHJenkins. Let's apply this to persons driving vehicles. How are cops supposed to know, on sight, the difference between a law abiding driver and a person driving with a suspended or non-existent license? Now, let's say they stop you for one reason only - to verify that you have a valid driver's license. Let's say they yell at you from 20 yards away, "Get over here!". Let's say they cuff you and stuff you in their cruiser while they wait for your license number to come back from the check. Then they release you and say, "Well you aren't illegal, have a nice day". How would YOU feel about that? What's the difference? There is much more chance that you would be driving without a valid license than there is a citizen carrying a firearm in a holster in an OC state is doing so illegally.