Amid street artist Banksy’s citywide guerilla art exhibit, “Better Out Than In,” some New Yorkers have been defacing — “going over” — some of his work. Why are graffiti writers attacking one of their own?

Short answer: They’re not. Longer answer: Banksy’s not playing by their rules.

Yes, the decades-old game of illegal art in New York has rules; when they’re broken, frontier justice gets meted out. Many graffiti writers believe Banksy has violated these rules and as such retribution is being delivered in front of the whole art world.

“I used to think other graffiti writers hated me because I used stencils,” Banksy told the Village Voice this month, “but they just hate me.” In fact, for all that the Voice and most other press call Banksy a “graffiti writer,” the graffiti community sees him as a “street artist.” This is an important distinction.

“Street art” is associated with whimsy and even gentrification — things the mainstream considers socially good, or at the least, nondestructive. Conversely, “graffiti” is a sign of poverty, criminality and a lack of order in a space. New York mayors have attacked it since at least John Lindsay.

In fact, many writers got into graffiti to offend mainstream sensibilities. Thus, many find Banksy’s media celebrity and the aggrandizement of his work offensive. Grounds enough for “going over” his work.

Graffiti writers’ main goal is fame — recognition, respect and reputation. Status is based upon the scale of the graffiti, how much attention it grabs and for how long.

Banksy’s work grabs international attention — so going over him grants a writer immediate status. It’s a quick and easy way to achieve fame that would otherwise take years. And it will be seen by anyone who goes to see a Banksy piece. Observers may think the writer is a jerk, but being considered a jerk by the mainstream is an added bonus.

Now consider a few rules of the illegal art game.

One is that writers have an obligation to maintain their work or “hold down their spot.” If they’re challenged by being gone over (an obvious act of disrespect to both the work and the writer) and don’t retaliate or fix their work, then they’re seen as having lost a battle — and to have been legitimately gone over. If you can’t hack it at the graffiti game, another writer is justified in removing your work.

Then there’s turf. New York City writers in particular strive to maintain a “locals only” policy on who gets to play in the graffiti game. Banksy is an English international art star; New York’s writers don’t feel he should get to just waltz in and grab all this attention. Many have been working for decades for their fame and they know how hard it is to get noticed in a city of almost 9 million. Banksy’s seemingly effortless notoriety rankles. There is a feeling that he is not entitled to the recognition he is receiving.

There is also a feeling that “Banksy started it.” Back in 2006, he went over a long-existing piece in London done by a writer named King Robbo. This act of disrespect by a street artist to a graffiti writer was highly publicized in graffiti circles. Many diehard writers considered it a throwing of a gauntlet and began to consider Banksy an enemy. Since they see Banksy as having initiated the fight, his work is not only fair game but also a target.

When Banksy, with his reputation and history, decided to play in the same playground as NYC graffiti writers, he picked some particularly tough playmates — who don’t care about mainstream opinion or even are pleased when it is negative.

So expect more Banksy pieces to get gone over. Graffiti writers play a complex prestige game while vying for the ability to appear on public spaces, and as far as they’re concerned Banksy is not exempt from its rules.

Tyson Mitman is a PhD candidate in media, culture and communications at Drexel University and editor of The Infamous magazine.