David Karpf points out how much worse it would all have been if he were not a white guy.

The controversy began earlier this week after reports of a bedbug infestation at the Times. Karpf, an activist and former Sierra Club board member who says he has been particularly disappointed with Stephens’s takes on climate change, made a joke about the conservative writer, whose columns have prompted some dismayed readers to cancel subscriptions.

“The bedbugs are a metaphor,” Karpf tweeted Monday. “The bedbugs are Bret Stephens.”

“He tends to write pretty lightweight, poorly researched columns about things that I know something about,” Karpf explained later. “So I’ve always seen him as this person that everyone complains about but we just can’t get rid of. He’s a bedbug.

The tweet seemed destined for obscurity. (Karpf did not tag Stephens’s now-defunct Twitter handle.) But then Stephens emailed Karpf and copied George Washington University’s provost. He invited the professor to come to his home, meet his family and call him a bedbug in person in an act that “would take some genuine courage and intellectual integrity on your [Karpf’s] part.”

“I’m often amazed about the things supposedly decent people are prepared to say about other people — people they’ve never met — on Twitter,” Stephens wrote. “I think you’ve set a new standard.”

Stephens’s response went viral as critics called it an overreaction. Karpf and others pointed to far more demeaning insults frequently aimed at other writers, especially women and people of color.

But he’s Bret Stephens, so that’s completely different…isn’t it?

Former Trump White House spokesman Sean Spicer, no stranger to online ridicule, laughed at Stephens’s indignation with conservative talk show host Sean Hannity, saying, “I think if that’s the worst thing that he’s been called, my goodness, take a look at my Twitter feed any day.”

“These guys can’t take a punch,” he said.

Some have defended Stephens. Letters published Saturday in the Los Angeles Times were critical of “name-calling” by Karpf, who detailed his takeaways from the spat with Stephens in the Times earlier this week.

Karpf wrote in that piece that he thinks he has received “remarkably little online abuse” stemming from the exchange with Stephens because he is a white man.

“If Stephens had directed his message to one of my female colleagues,” he wrote, “they would have faced much more online vitriol. … Many women with a public platform receive a death threat with their daily morning coffee.”

That reality, Karpf told The Post, has made Stephens’s decision to amplify his bedbug tweet all the more baffling. By the end of this week, the professor’s Twitter feed was returning to normal. The media requests were thinning. The smart thing for Stephens to do, he said, would have been to let the dust-up die — a lesson he discussed earlier this week with students of his class on political communications.

“It should have ended there,” Karpf said. “And then he decided he wanted to dunk on himself again.”

I expect what he thought he was doing was explaining to the waiting world how he was right and Karpf was wrong and everybody who thought he overreacted was wrong and look out it’s the left-wing Nazis. The problem is that that’s all bullshit, so it didn’t work out for him.