Thursday was 93-degree New York at its most relentless.

Hung-over Knicks fans collided on the morning subway with tourists in soccer jerseys coming in for the World Cup.  

For the 50 or so people in a cool Brooklyn courtroom, the delirium outside was nonexistent.

They remained anchored to the horrors of 2020, and the city’s 47% spike that year in murders.  

The proceeding was straightforward: Judge Deepa Ambekar sentenced 30-year-old William Freeman to 18 years in prison on a manslaughter plea, for fatally shooting Ethan Williams, age 20, in the early morning of Oct. 24, 2020, as Williams sat on a Bushwick stoop with friends. 

Freeman hadn’t targeted Ethan: He shot — eight times! — toward the group on the stoop, because he thought a rival gang member was there.  

It took more than two years of NYPD work — and a traffic stop over a minor violation — to make an arrest.  

The courtroom spectators neatly divided themselves: on the left benches, the killer’s family and friends, many wearing blue-and-orange Knicks t-shirts.  

On the right, in crisp workplace attire, were 25 out-of-towners who had flown in to support Ethan’s parents, brother and girlfriend as they spoke in court.  

They came at their own expense, because Ethan himself was a tourist.  

A first-time visitor to New York, Ethan had arrived from Indianapolis for a skateboarding tournament and to see the sites featured in his favorite Spider-Man films, his father Jason told the courtroom.  

Ethan, an aspiring filmmaker, saw the city as a “cinematic playground . . . to come to New York for the first time was a big deal,” Jason said. 

But mostly he wanted to meet people, which is why he was sitting on the Brooklyn stoop of his AirBnB.  

Jason told Ethan what any nervous parent tells his kid: “The last time I texted to him  . . . was keep your head on a swivel. New York isn’t home.”  

Instead, as Jason told his son’s killer before the judge, “You entered the story and violated our family, and you introduced an evil into our lives.”  

And while New York has moved on from Ethan’s murder, it’s not over for the Williams family.  

“For a lot of people, Ethan’s death was a headline,” Ethan’s mother Susan said.

But “It’s what I think of when I wake up and what I think about when I fall asleep.”  

Yet the family publicly forgave Freeman Thursday —  and Susan counseled him to take his debt to them seriously by becoming a better person in prison.  

“William, I want to talk to you now,” Susan said. “You are beloved. I want to acknowledge today your family’s loss . . . Violence multiplies suffering.”  

Freeman was remorseful, apologizing multiple times.  

“I think that’s not gonna help nothing,” he said. “What I did was terrible.” 

By the time Ethan’s parents, brother and girlfriend were done speaking, even the court stenographer was crying — and the sniffles from Freeman’s family’s side of the room were just as audible as those from the Williamses’ side.  

But Freeman’s contrition underlines New York’s failing.

The city and state should have prevented this crime. 

Before Freeman shot toward Ethan multiple times, he had racked up nine arrests, including for gun possession.

In January 2020, cops caught him stealing baby formula from a Manhattan store while toting a switchblade.  

But New York’s “reformed” criminal-justice system released him — then failed to re-arrest him when he skipped court appearances. 

That left him free to shoot Ethan, and to seal himself a long prison sentence. 

New York is safer now, with murders at record lows.  

And Ethan’s family had a role in that.

Over the past half-decade, public and political pressure has pushed Gov. Kathy Hochul to tighten our criminal-justice laws — and some of that pressure came from Ethan’s family.

Jason Williams himself wrote a front-page column for The Post in 2021.  

“When Ethan died, a promise I made to myself, a promise I made to him, if I can bring any good to this, I would,” Jason told me Friday.

And he has.  

That’s hard work. 

As Jason told me, “The murder is the first trauma. It’s just repeated traumas after that” — having to push the criminal-justice system along at every step.  

No one involved in this case can explain why it took three-plus years since Freeman’s arrest  to achieve a plea bargain; the evidence is on film.  

And the laws are still too loose, so the potential for disintegration lurks, as the anarchy in Midtown Manhattan after Wednesday’s Knicks win showed.  

Jason and Susan, on their four visits to New York since 2020, have amply experienced its disorder: They’ve been verbally harassed on the streets around Times Square.  

Will Jason return to the city? “I hope not.” 

But he can know that Ethan’s too-short trip made New York a better place.  

Nicole Gelinas is a contributing editor to the Manhattan Institute’s City Journal.