So you would feel horror---or "concern"---to see an ordinary citizen with a firearm? Then I would think guns would add horror to the film IF they are used by the "non-villains."

Why do you note non-villains? What are you getting at? I sense you're trying to get at something, but you haven't revealed it yet. ::big grin::

I wouldn't necessarily have concern at seeing "an ordinary citizen" with a firearm. When I wrote "in public" I meant, let's say, in my state where it would be illegal, if I saw a stranger holding a pistol in Walmart in the frozen fish section, then yes, I would be immediately concerned -- which would trigger me to analyze the person and situation... at it's conclusion, I may very well no longer be concerned.

A non-villain in a horror film like The Thing 82, or a non-villain in Evil Dead, or a non-villain mentally disturbed person, in a flash could become either villainous or simply dangerous to the other non-villains. ::wink::

Just trying to gauge your view on guns. My difficulty is squaring two somewhat incompatible views: guns are not objectively horrifying, yet you would be horrified to see an ordinary citizen carrying one in public.

I would experience little horror seeing a holstered one in public, but if it were drawn and aimed would be quite frightened.

They do in some horror movies.

This is true. It depends on the setup. I saw a movie recently which I might review here, that when the character gets a gun it becomes even more scary because you know they are crazy and will use it. And not miss. They aren't the type to play around pointing a gun.

You can't see it in the gif but afterwards he creeps around the car scaring the crap of out that woman, before killing her.
I'd say that's an effective use of a gun in a horror movie.