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President Trump’s disinfectant comment Thursday was an eyebrow raiser, though not worthy of the acres of hate media it spawned for days.

It didn’t deserve Nancy Pelosi’s malicious distortion that “the president is asking people to inject Lysol into their lungs.”

Nor did it merit the pompous open letter from four journalism professors to network TV heads demanding an end to live coverage of the president’s briefings because they are a “serious public health hazard.”

But why does the president keep giving his enemies ammunition to ridicule and slander him during marathon daily coronavirus briefings?

He is trying to use sales techniques on a virus, as a business friend notes, and in case he hasn’t noticed, it doesn’t work.

It isn’t working for him in the polls, either. The “sleepy guy in the basement of a house,” as he called Joe Biden, is beating him, just by being invisible. Might be a lesson there.

No, the president did not urge Americans to “drink bleach” or inject Lysol into their lungs. But to understand what went so wrong Thursday, you need to factor in the destructive relationship Trump has fostered with the media and the loose talk he indulges in during more than 50 briefings since the crisis began. All the careful data-driven presentations from scientists are blown away when the president commandeers the podium for his own mercurial purposes.

On Thursday, Trump was visibly excited by a presentation on the effect of sunlight and humidity on the virus by William Bryan from the Department of Homeland Security.

“We know that summerlike conditions are going to create an environment where the transmission can be decreased,” said Bryan.

Tests on COVID-19 in saliva droplets on surfaces and in the air show it dies more quickly in sunlight, heat and humidity, a promising development with summer on the way.

For instance, the virus rate of decay on a door handle is 18 hours indoors at a temperature of 70 to 75 degrees with 20 percent humidity but, with 80 percent humidity in sunshine, its half-life is just two minutes.

DHS also has been testing disinfectants, including bleach and isopropyl alcohol.

“Bleach will kill the virus in five minutes, isopropyl alcohol … in 30 seconds,” said Bryan.

When Trump took to the podium afterward, he addressed himself directly to Bryan: “Supposing you brought the light inside the body, which you can do either through the skin or in some other way? And I think you said you’re going to test that, too. Sounds interesting.

“And then I see the disinfectant, where it knocks it out in a minute, one minute. Is there a way we can do something like that by injection inside or almost a cleaning? … You’re going to have to use medical doctors, but it sounds interesting to me.”

It was an undisciplined brainstorm of no consequence, but it detonated a nuclear explosion in a room filled with hostile journalists, beamed live to millions of Americans.

The public doesn’t want the president playing scientist. We have scientists for that.

His job is to be commander in chief, make the tough calls on reanimating the economy, leave the science to the experts, and project strength and composure in the face of a pandemic that has killed more than 50,000 Americans and put millions out of work.

In fact, Trump supporters quickly tweeted links to research studies that might justify the president’s questions, one from Cedars-Sinai into ultraviolet light as an antiviral treatment, and another from a university in Japan involving the inhalation of ethanol vapor.

But if the president wants to make left-field suggestions for research topics, let him do it behind closed doors, instead of confusing the message of steady reassurance the briefings are supposed to convey.

The worst possible spin was put on Trump’s ruminations by gotcha merchants like CNN’s Jim Acosta, and the whole ridiculous story blew up on Twitter, forcing Lysol and Clorox to issue statements warning against ingesting their products.

The president only made it worse the next day by pretending he was just being “sarcastic” to reporters.

By Sunday, Dr. Deborah Birx had had enough. Asked on CNN if Trump’s comments bothered her, she said, “I think it bothers me this is still in the news cycle.”

Birx’s attitude is responsible and generous-spirited. She doesn’t demonize the president. She clearly regards him as well-meaning and worthy of respect.

On Saturday, she told Fox News she didn’t believe he had put anyone in danger with his “musings.”

“No, when [he] gets new information, he likes to talk that through out loud and really have that dialogue.”

Trump-haters try to cloak their malevolence with the paternalistic pretense that they are protecting Trump voters, whom they regard as morons, from self-harm. Yet they revel in news of any suspected Trump supporter who dies of coronavirus, as if it is a just comeuppance.

The president’s actions have been sound. His decisiveness in banning flights from China in January was crucial. He has followed medical advice to the letter.

But he doesn’t get the credit he deserves because he trawls for acclaim in all the wrong places.

Moore turns greens red

Michael Moore is under fire from greenies for his new documentary, “Planet of the Humans,” which exposes the renewable-energy scam. But he deserves a medal.

The movie, which had 1 million views on YouTube in its first 48 hours, shows up eco-luminaries such as Bill McKibben and the Sierra Club as conflicted phonies. It shows that the solar- and wind-power industries consume more fossil fuels than they save and cause untold environmental degradation.

Well-meaning idealists should realize they have been hoodwinked by the climate movement.

It took a leftist to show us how to remove culture wars from environmental protection. Now we can get back to the genuine goal of taking care of our planet, rather than making Al Gore rich.

In times of trouble, NYers lend a band

A heartwarming story of neighborly love, pandemic-style, comes from The Bronx.

Retired NYPD Lt. Artie Dallas organized a police pipe-and- drum band Sunday to perform a surprise street concert in front of his neighbor’s home for the man’s 80th birthday.

Norman Harris, a retired TWA vice president and proud member of the City Island Coast Guard Auxiliary, was overcome as he stood on his porch, in face mask and Yankees jacket, while the band piped and friends and family cheered.

Just one example of how the lockdown has brought out the creative best in our city.