When I was a teenager, my dad exposed me to Eric Hoffer's "The True Believer," which warns of the dangers of rigid ideology. We have seen it in the far right's disdain of virtually all government programs and its dislike for unions -- and in the hard left's diametrically opposite outlook.

We are witnessing that rigidity in the NYC charter schools battle. A steadily increasing number of such schools have been co-existing in public school settings -- until now. Mayor Bill de Blasio's reversal on approvals of three such schools has made it clear he is no fan of charter schools.

"Right now, our kids are being evicted," said Eva Moskowitz, the head of the Success Academy charter schools, three of which were the ones axed by the mayor. "You're going to have to ask Mayor de Blasio what the motivations are for a decision that will hurt so many children."

But de Blasio, the target of protests in Albany Tuesday, is unbending. "We were handed a series of last-minute moves by the Bloomberg administration approving a number of co-locations that we feel were ill-advised," he said.

The teachers union has applauded de Blasio's decision. "I'm glad the DOE has taken an important first step in vetoing some particularly troublesome pending co-locations," United Federation of Teachers chief Michael Mulgrew said. The UFT opposes charters partly because they hire nonunion teachers. Charters that outperform public schools offer a path to student success for inner-city parents who can't afford private schools. The fact that de Blasio didn't target failing charter schools is telling. One of the programs losing its space is Success Academy's Harlem 4, where student math and reading scores exceed city averages.

De Blasio's hard line puts him at odds with both Gov. Andrew Cuomo and President Barack Obama, who support charter schools.

Are all charter schools successful? No. But it seems that anything that works to help NYC schoolchildren, whether in charter or conventional schools, is worth emulating. Unfortunately, sometimes those in charge refuse to listen.

Why is that? Hoffer had the answer: The true believer "cannot be frightened by danger nor disheartened by obstacles nor baffled by contradictions, because he denies their existence."

Playwright Mike Vogel blogs at newyorkgritty.net.