On the surface, it appeared that a major New York hospital had gratefully accepted a $100 million gift from a philanthropic family with a long history of donating to the arts, higher learning and medicine.

But the new wing at New York-Presbyterian Hospital inspired a bizarre protest last weekend by activist groups including the NAACP New York State Conference, the New York State Nurses’ Association and the hospital-employee union SEIU Local 1199.

Surely there had to be a catch to the hospital wing. Why else would it be a source of such distress? Was there a provision that would cause all the nurses in the new wing to be replaced by voodoo priests?

Was the hospital secretly to be used as a gay re-education camp that would seek to use a combination of systematic exposure to Sylvester Stallone movies, shock therapy and prayer to destroy homosexual impulses in its patients?

Or was there simply to be a large sign posted at the door that read, “Sorry! Whites only.”

It turned out that none of these factors was at play. The new structure will simply be an ordinary wing of a hospital doing regular hospital stuff like saving lives, charging $25 for a Tylenol and (equally important to the unions, you would think) employing lots of healthcare professionals. The $100 million gift was the largest in the hospital’s history.

No, the only thing the liberal interest groups didn’t like about the new hospital wing was its funding source: the philanthropist known as David H. Koch. The new wing was gratefully to be named after Koch, who along with his brother Charles stands as one of today’s great philanthropists.

Among the many David Koch gifts to this city alone are a previous $15 million to New York-Presbyterian’s Weill Cornell Medical Center, $30 million to Sloan-Kettering Cancer Center, $25 million to the Hospital for Special Surgery, $20 million to a dinosaur exhibit at the American Museum of Natural History, $65 million to the Metropolitan Museum of Art and $100 million to the Lincoln Center theater that is home to the New York City Ballet and the New York City Opera.

If you’re a ballerina, an opera singer, a dinosaur or just a person who has been or could potentially become sick in this city, you should think of David Koch approximately the way you think of, say, Derek Jeter, only not really because Jeter profits from you whereas you profit from Koch.

No hospital receiving funding from George Soros has to worry about a picket line forming outside, even though Soros funded Lynne Stewart, the radical lawyer who served four years in prison for providing material support to al Qaeda terrorism. But let’s not sweat it. It’s not like Soros backs terrorists. He merely backs those who back terrorists, so it’s cool.

The anti-Koch groups held their protest on International Women’s Day to signify that this was a woman’s issue: It turns out a group called the Center to Protect Patient Rights, which also receives some Koch brothers largesse, has given $1 million to Susan B. Anthony’s List, a pro-life group. And the nurses who have made it their calling to protect human life? They don’t like that.

It’s an update of the “You can’t fight in here, this is the war room!” line from “Dr. Strangelove”: Today they won’t let you near a hospital — even to drop a bag of money at the door and go away! — if you sound too gung-ho about preserving life. Never mind that it’s not even clear either Koch is funding Susan B. Anthony’s list, or that $1 million — less than one percent of the amount that David Koch has given to New York City hospitals — is what spills out of his pockets every time he gets off the sofa.

The Susan B. Anthony connection makes him an ideological enemy, just as the CPPR’s opposition to ObamaCare does. A press release accompanying the protest said the Kochs wanted to “defeat and repeal health care for all Americans.” And what a sneaky way they went about it: by giving hundreds of millions of bucks to hospitals!

Here’s an idea for the nurses and the NAACP: Go form a picket line at the White House. Make your opinion known to that heartless fellow who is responsible for leaving a group of Americans equivalent to the entire population of New York and New Jersey without coverage.

The liberal groups won’t be doing that, of course, for the same reason they held the absurd protest in the first place: because they are effectively arms of the Democratic party. As Democrats first (and hospital workers second) they got this week’s message (also last year’s, and the year before that’s) that winning in November is about trashing the Koch brothers for their funding of conservative causes and free-market ideas.

First, the party hopes to plant in the public imagination the idea that the Kochs are Satan and Lucifer — a point to be made with assistance from media friends such as The New York Times, which printed yet another Koch-questioning story after their spiritual leader Harry Reid announced that the Brothers K were “un-American.”

Then, Democrats imagine, groups that receive Koch backing will either have to decline further funds or be smeared as demonically possessed. The Democratic Senatorial Campaign Committee, playing off the fact that Koch is pronounced “coke,” punned that “the GOP is addicted to Koch.” But it’s slightly deranged of the Democrats to press their theme that campaign spending is of more than trifling concern to the average American. A better way to put the case is that Democrats are suffering from psy-Koch-sis.