In Michigan, at least, the showing of a firearm in an attempt to intimidate, is considered "brandishing" and will get you 90 days and a hefty fine. Class A misdemeanor.
Michigan probably isn't an open carry state. Brandishing involves purposefully showing a weapon with the intent to intimidate. If the gun never leaves the holster, he never placed his hand on it and never referred to it, he wasn't brandishing.
If someone isn't mature enough to have a disagreement with someone carrying a gun without letting their imagination terrify them, they need to go finish the sixth grade.
It's precisely that sort of immature, "He's gonna shoot me!" whining that has nearly destroyed the second ammendment in the first place.
If you feel that someone else's wearing a gun restricts your preferred course of action, you are your own witness that you shouldn't be doing that.