Victor Navasky, who died this week aged 90, was famous for his books about the McCarthy period in the 1950s and Robert Kennedy’s justice department in the 1960s, his longtime editorship of the Nation magazine, and positions at Columbia University including chairing the Columbia Journalism Review.

What almost no one remembers is how his homophobic reaction to a famously homophobic article in Harper’s magazine led him to commission the most pro-gay piece the New York Times had published up to that time – a foundational document which appeared in 1971, at the dawn of the movement for gay liberation.

In September 1970, Harper’s, a famously liberal magazine, published a notorious article by Joseph Epstein: Homo/hetero: the struggle for sexual identity.

The earliest long-form reaction to the budding gay movement in a liberal magazine, the article appeared 14 months after police raided the Stonewall Inn, a gay bar in New York’s Greenwich Village, sparking famous riots.

Epstein wrote that homosexuals were “cursed … quite literally, in the medieval sense of having been struck by an unexplained injury, an extreme piece of evil luck”. He added that nothing any of his sons could do “would make me sadder than if any of them were to become homosexual. For then I should know them condemned”.

Gay activists were horrified and soon staged a sit-in at the Harper’s office. As each employee arrived, a protester greeted them: “Good morning, I’m a homosexual. Would you like some coffee?”

Merle Miller, a prominent novelist and magazine writer, was a regular contributor to both Harper’s and the New York Times Magazine. He had never told another straight person about his orientation.

The week after Epstein’s article appeared, Miller lunched at Chambertin, a French restaurant that was a favorite Times hangout, with his two editors at the Times Magazine: Gerald Walker and Victor Navasky.

Twelve years later, the Columbia Journalism Review (not then edited by Navasky) reported what happened.

This was an era when the Harris Poll reported that 63% of Americans considered homosexuals “harmful” to society, and the official manual of the American Psychiatric Association stated that all homosexuals were mentally ill.

Miller asked Navasky and Walker what they thought about Epstein’s diatribe. Both editors told him they thought it was a great article.

Miller exploded: “Damn it, I’m a homosexual!”

He then explained why the article was actually an abomination.

Navasky responded to Miller’s outburst with an openness of which almost none of his heterosexual colleagues were capable.

“Since you hated the piece so much,” Navasky told Miller, “you should write the response to it.”

Miller did so. When his piece, What It Means To Be a Homosexual, appeared in January 1971, James Baldwin and Allen Ginsberg were two of the only openly gay writers in America. But Miller was the first ever to come out in the pages of the New York Times.

His piece had all the knowledge, nuance and humanity Epstein’s lacked. The only things the two writers agreed about were that “nobody seems to know why homosexuality happens” and, surprisingly, 50 years later, the great fear that a son will turn out to be homosexual.

But Miller added: “Not all mothers are afraid that their sons will be homosexuals. Everywhere among us are those dominant ladies who welcome homosexuality in their sons. That way the mothers know the won’t lose them to another woman.”

For a 20-year-old gay man like myself, who had never read anything positive about gay people in the New York Times, Miller’s article was a gigantic source of hope.

Forty one years later, Miller’s piece was republished as a Penguin Classic paperback, On Being Different: What It Means to Be a Homosexual. I wrote an afterword. I also invited Navasky to appear at a bookstore, for a panel discussion of his role in the gestation of Miller’s piece. He was delighted to participate. It was the first time he publicly described his momentous lunch with Miller.

• Charles Kaiser is the author of The Gay Metropolis: The Landmark History of Gay Life in America