Jason Bourne (Matt Damon) eluding enemies in Universal Studios’ “The Bourne Identity” (2002). (Universal Studios/AP.)

Actor/producer/screenwriter/humanitarian/dreamboat Matt Damon is not one who often runs afoul of liberals. He stumped for Barack Obama — at least until the two “broke up,” as Damon put it, over drone warfare and NSA surveillance. He runs a charity that focuses on water programs in Africa. He even wants to stop the delivery of junk mail because it’s not environmentally friendly.

But Damon seemed to spend much of his liberal political capital on Sunday. In an episode of the HBO series “Project Greenlight” — a reality show, created by onetime Hollywood Cinderellas Damon and pal Ben Affleck, in which newbies compete for a chance to make a $3 million movie — Damon held forth on diversity in the entertainment biz. He said, more or less, that it’s not always important.

“When we’re talking about diversity, you do it in the casting of the film, not in the casting of the show,” Damon said. Translation: Diversity is needed among actors onscreen, but not among filmmakers behind the camera.

What was worse, for many viewers: Damon’s remark came in conversation with Effie Brown, the African American producer of many films, including last year’s critically lauded “Dear White People,” and a judge on “Project Greenlight.” Thus, it seemed that a white male — a very famous, Oscar-winning white male — was lecturing a lesser-known artist of color on how Hollywood works.

Brown was visibly shocked: “Wow, okay,” she said. She had been discussing the need for sensitivity in a script with racially charged subject matter.

“I just want to urge people to think about, whoever this director is, the way they’re going to treat the character of Harmony, her being a prostitute, the only black person who gets beat by her white pimp,” said Brown, the only black woman in the room at the time.

Damon doubled down in an interview later in the show.

“It seems like you would undermine what the competition is supposed to be about, which is about giving somebody this job based entirely on merit,” he said.

Outrage on social media was directed to the hashtag “Damonsplaining” — a take on “whitesplaining,” defined by the Urban Dictionary as “the paternalistic lecture given by Whites toward a person of color defining what should and shouldn’t be considered racist, while obliviously exhibiting their own racism.”

“You highlighted the problem w/even well-meaning white ppl,” one user wrote Brown on Twitter. “They still think they know better how to represent [people of color] than PoC.”

It wasn’t just the Twittersphere that was up in arms. There was also the online petition-sphere. One such petition demanded the actor apologize to Brown.

“While raising concerns that an all white male directing team might not be the best choice to properly direct a movie about a Black female prostitute who is slapped by her white pimp — Matt Damon decided to cut her off and whitesplained diversity to Effie Brown,” an online petition read. “Damon told her that diversity behind the camera doesn’t matter. Matt Damon couldn’t be more wrong.”

Conservative news outlets, meanwhile, offered outrage about the outrage — or just cackled. Breitbart: “Left Eats Liberal Matt Damon for Offering Opinion about Diversity.”

“The left’s been wetting its pants over this for the past 24 hours so we can’t be more than a day away from a groveling Damon apology,” the conservative Web site Hot Air wrote. “Let’s get you up to speed so that you can enjoy the blue-on-blue while it lasts.”

Damon, not known for his social media presence, has remained silent on the exchange so far. Brown, however, offered her take.

“Ooof!” she wrote. “Wow! Okay. Thank you for watching the show and getting a great conversation started. I can’t wait to hear you on the other episodes!”

Perhaps Affleck — who warned over the weekend that this season of “Project Greenlight,” which was revived after a decade-long hiatus, was “the riskiest season we’ve ever done” — was right.