The guy was an asshole because he didn't understand no means no. Granted Cameron may have been less than polite but who knows what else is going on for him at that moment. There are times when people in the film industry are HUMAN and will react as humans do. Not to mention the signature on that poster would make it sellable, if the guy wanted a personal autograph and it wasn't such a set up he might have gotten it. Just because you work in film and are successful at it doesn't entitle the public to intrude into your personal space any more than it should allow witnesses to harass people in the same situation to talk about the Watchtower.
The fans don't make someone successful, the QUALITY of the work CREATES fans who get absolutely everything they are entitled to when they walk out of a theatre happy, and get a bonus if it was good enough to see over and over again. It's flattering to get the attention from the public, but it can become very tiresome as an individual when the public treats you as if they are entitled to more no matter how you feel about it.
I only work behind the scenes and very rarely in front of the camera so I don't even get a real taste of it except for when I'm out with the crew or an actor/actress. I've seen what they have to deal with and you can't really understand what may have happened until you are in the situation.
Every job is easy to the people who aren't doing it.
WLG