“Broken windows” policing is a strong deterrent to more serious crimes. But the NYPD’s mango-sale crackdown at a Brooklyn subway station was just goofy when cops seem unable or disinclined to go after the real bad guys right under their noses.

Anyone who uses the Broadway Junction subway station in Brooklyn — which frightened me as a child and feels even creepier today — knows what might be in store. The dilapidated, century-old, mostly elevated iron structure where East New York and Ocean Hill touch is Brooklyn’s third-busiest subway hub. With 100,000 daily users, it’s intimidating despite omnipresent crowds that might lend a sense of safety elsewhere.

Mayor Eric Adams defended the cops who cuffed the hapless mango merchant last month, an incident that went viral on YouTube: “Next day, it’s propane tanks being on the subway system. The next day, it’s barbecuing on the subway system. You just can’t do that.”

Now propane tanks wouldn’t be a good idea at all — but they’re not what straphangers and Metropolitan Transportation Authority employees worry about. By arresting a lone fruit seller, the NYPD is sending a disingenuous message (“See, we don’t tolerate even petty lawbreaking at Broadway Junction”), prompting the question: Well, if the cops are so tough on criminals there, why is the station — where five subway lines converge — so dangerous?

Asked to provide statistics on Broadway Junction crime, the NYPD replied, “Data is not tracked to that level of specificity.”

But we can read the papers. Two weeks ago, a knife-wielding man slashed a 52-year-old man and tossed him onto the A-line track. In February, a 27-year-old man was shot in the chest on the L-train platform. Last August, a 47-year-old man was knifed in the stomach while riding an escalator.

At all times, Broadway Junction conveys a sense of imminent chaos. In 2018, when crime was much lower, it was the site of the city’s only subway murder. It led all the city’s 450 subway stations for gun-possession arrests back in 2014 — a ranking unlikely to have changed much if at all.

With so much actual and potential mayhem lurking in the cyclopean junction’s labyrinth of elevated and underground platforms, mile-long escalators, myriad stairways and open-air track crossovers, what’s the NYPD doing?

Busting a low-income woman for selling mangos and other fruits without a license. (At least her goods were fresh, unlike the packaged junk food sold at a snack window where condoms and other daily necessities are available for purchase.)

That is, when the uniformed officers are doing anything at all. The citywide command policy that floods stations with cops but lets them idle on mezzanines rather than aggressively patrol platforms is on ample display all the time at Broadway Junction — despite claims to the contrary by Adams, NYPD Commissioner Keechant Sewell and MTA head Janno Lieber.

I often pass through the station en route to real-estate sites. It’s one-stop-shopping for all manner of unsavory and antisocial acts, including a guy on the underground A-train platform Tuesday afternoon peddling drugs in a low voice. (My journalistic curiosity as to exactly what wares he offered was overwhelmed by a survival instinct that propelled me past him as fast as I could go.)

While the man plied his trade — and as rowdy youths shouted obscenities and freaked out people at the top and bottom of the escalators — three cops stood stationary behind an iron bicycle-rack-type barricade on the ground level near the token booth. Were they trying to protect themselves rather than the public?

Busting fruit sellers while ignoring serious threats isn’t broken-windows policing — it’s responsibility-avoidance.

More fruit sellers, not fewer, might actually be good for Broadway Junction. A recent crackdown on unlicensed vendors in the area outside the station cleared its outdoor plaza of the hot dog and French fries carts that lent a semblance of community.

The neighborhood around Broadway Junction is one of Brooklyn’s saddest sights — a desolate jumble of hard-to-navigate streets and empty lots. Elevated J and Z tracks above Broadway dip ominously low and discourage new investment. The area is all but devoid of stores and places to eat and is notoriously dark and scary at night. The way to the LIRR East New York station a few blocks away might be the scariest inter-transit route in town.

The way to make it safer is to aggressively challenge drug dealers and troublemakers at Broadway Junction — and wait ’til they’re gone before persecuting a woman trying to make an honest living.