Rarely has a group of people exposed their true disdain for all others as clearly as the New York police officers who turned their back on Mayor Bill de Blasio at the funeral of Rafael Ramos. They wanted to send a message, that they demand to be treated better than all others. They sent a message, but not the one they thought.

They are given training, guns and shields, not to mention a paycheck and a pension, to do a job. That’s not enough for them. They demand two more things to which they are not entitled: impunity for their violence and protection from harm above all others.

The NYPD was given the nickname “New York’s Finest.” They are not. Some may be, but the ones who turned their back have no business wearing a shield. They are untrustworthy. They are ignorant of their duty. They care only for themselves and their own; they do not care about “them.”

These cops are New York’s disgrace.

Like others, I sought to quiet the inflammatory rhetoric after the murder of officers Ramos and Wenjian Liu. Their death, like any senseless death, is a tragedy. But not a greater tragedy than the needless killing of Eric Garner and others.

A cop’s life is not more valued than anyone else’s life. Some cops think they are. They should not be cops.

As if to emphasize the selfishness, the ignorance, the wrongfulness of the choices of whom to hand a shield and gun, following their act of disgrace, cops attending Ramos’ funeral then did what puny, selfish, ignorant children do. They embarrassed themselves further.

What a great day, attend a funeral, turn your back on a mayor, get drunk and violate the same law you use to arrest, and sometimes harm, others, all the time wearing the uniform given you by the people you are supposed to serve.

But this was more than a mere demonstration of selfish, infantile behavior, that they cannot be trusted with a gun and shield. No, this was a threat, a challenge to de Blasio. Adore us. Support us over all others. Back us to do whatever we do. Or else.

They did this before, to New York’s only black mayor, David Dinkins, and it cost Dinkins his mayoralty. He tried to massage his way beyond the cops’ threat, and it failed. The police would accept nothing less than complete loyalty. They sought to bring Dinkins down and they did.

This is an opportunity for Mayor de Blasio to decide whether the police serve the city, or the city serves the police. This is a test of Commissioner Bill Bratton’s fortitude, whether he will use his clout to change this frontal assault on the people and government of New York City. The cops have made their position clear.

It is time to bring the cops down. New York City cannot succumb to extortion, whether from outside or its own police force. They cannot own this city. They cannot win this challenge. The City cannot give in to their demand to let them kill with impunity, to protect the cops above all others.

They should not be killed, but they cannot kill any more than anyone else. This is the time to do something to change things. The police officers of the NYPD issued the challenge. They brought this upon themselves. They must lose.

If a cop does not accept the basic premise that his position and authority stem from a duty to serve the public, then he has no business being a cop. Every cop who turned his back on the Mayor should be punished. Every cop who does needless harm to another human being must be fired. Every cop who refuses to perform his function with honor and integrity must be gone.

If you can’t do that, you can’t be a cop. If cops refuse to do that on your watch, you must take away their gun and shield. And if cops threaten to hold a city captive unless it capitulates to their demand, then they are a cancer within the government that must be cured.

This is not a matter of sweet words to cool hot heads. The mayor can’t talk his way out of this threat. This is a matter of people who cannot be permitted to wear a gun and shield because they do not grasp why they have been so entrusted, and have demonstrated that they are unworthy of that trust. This must end. The time has come to turn our backs on the Police.