Anthony Paletta tackles the question for us and it's worth a quick read. (Remember, I'm a movie buff.)
Actually, it's an old question that arose most prominently in the early 1970s when liberal (what else?) film critics uniformly disparaged two of the most famous of the genre, Death Wish and Dirty Harry. But I'd suggest asking the question the other way. That is, why do most people love vigilante films?
The answer is easy. The appeal is justice itself.
Justice denied for any reason, even for the sound reason of a decent society taking great care to afford the accused due process, a jury trial, and an opportunity for appeal is still justice denied and justice denied wounds the body politic. When people know it's being denied, but then witness it being delivered, even, or perhaps especially, in the form of a well-crafted movie melodrama, they almost reflexively cheer.
There is absolutely nothing unusual about that.
What is unusual, perverse actually, is an ideological posture so rigid that one disciplines oneself to not only sit on one's hands, but even to hiss and boo when the bad guy finally gets it.
BY THE WAY....
Paletta arrives here as well, but I would also say that, among many other things, that perverse informing ideology can be defined by an insistence that all or most crime can be explained and excused by poverty or some other "root cause", along with a stubborn refusal to accept anything like the notion that evil may actually exist.
Which put me in mind of a telling exchange from another great film, The Dark Knight, the second in the most recent Batman series, the one with Heath Ledger as the "Joker". The conversation is between Christian Bale as Bruce Wayne (Batman) and Michael Caine as Alfred, Wayne's butler.
Wayne: Targeting me won't get their money back. I knew the mob wouldn't go down without a fight, but this is different. They crossed the line.
Alfred: You crossed the line first, sir. You squeezed them, you hammered them to the point of desperation. And in their desperation, they turned to a man (the Joker) they didn't fully understand.
Wayne: Criminals aren't complicated, Alfred. Just have to figure out what he's after.
Alfred: With respect, sir, perhaps this is a man that you don't fully understand, either. A long time ago, I was in Burma. My friends and I were working for the local government. They were trying to buy the loyalty of tribal leaders by bribing them with precious stones. But their caravans were being raided in a forest north of Rangoon by a bandit. So, we went looking for the stones. But in three months, we never met anybody who traded with him. One day, I saw a child playing with a ruby the size of a tangerine. The bandit had been throwing them away.
Wayne: So why steal them?
Alfred: Well, because he thought it was good sport. Because some men aren't looking for anything logical, like money. They can't be bought, bullied, reasoned, or negotiated with. Some men just want to watch the world burn. (my italics)