Some of the hundreds of photographs sent to the SBA. SBA via Flickr

While the very public spat plays out, the homeless have become a nonconsenting part of the debate, activists say.

“The union is using the homeless as pawns to support another agenda, saying, ‘You let us do overly aggressive policing or we’re going to become an out-of-control, blighted city like we were in the 1980s and 1990s,’” said William Burnett, a co-chairman of Picture the Homeless, a civil rights and housing advocacy group.

Burnett, who has experienced homelessness, said he believed New York has changed for the better over the last two decades, in part thanks to the work the NYPD did 20 years ago. But he added that the apparent success does not grant officers the right abuse citizens.

In his letter to members, Mullins doesn’t offer solutions to homelessness or suggestions for how police can help people living on the street. He didn’t return multiple requests for comment from Al Jazeera. But others say a different tack is necessary if relations between officers and members of the city’s homeless community are to improve.

DeLacy Davis, the head of the National Coalition of Law Enforcement Officers for Justice, Reform and Accountability and a retired 20-year veteran of the Orange County, New Jersey, police force, said the SBA was wrong to politicize policing of the homeless.

While the union has a responsibility to advocate for its members’ safety and pay, they shouldn’t “do it on the backs of the homeless or groups in the community that can’t defend themselves,” he said. “It’s just the wrong fight.”

To help the homeless, he said, officers need to get to know the people who are on their beat and respond with the reflex of helping, not punishing. This is especially true for the homeless who are mentally ill, he said.

“Consider a naked man yelling in street, cursing and screaming. Well, he is naked. But there is no reason for me to shoot him,” Davis said. “I can see he’s not a threat to me from a distance.”

But Burnett doesn’t trust police to do the right thing.

“If they post pictures of vulnerable homeless people on the Internet, that reflects a real contempt on their part,” he said. “Would you trust somebody that has that much contempt to act in good faith?”

At Penn Station, Jackson said she would like to see officers provide direction to resources from the city, acting more as social workers than bullies.

Ernest Kimble, a 57-year-old homeless person, suggested officers should approach them with food rather than cameras if they want to improve relations.

"Maybe they could hand out sandwiches to us," he said.