Swamp Rabbit couldn’t get over it.

First the 16-year-old, internationally famous environmental activist Greta Thunberg delivered her save-the-planet message to tens of thousands of protesters in Battery Park. Then she went to the United Nations and made a similar speech, but in a more accusatory style, to so-called world leaders who aren’t doing enough to slow global warming.

Climate change deniers on Fox News hit back — hacks like Laura Ingraham and some guy named Michael Knowles, who referred to Thunberg as “mentally ill” because she has Asperger syndrome.

“‘Mentally ill compared to who?” Swamp Rabbit said as we watched the clip from Fox. “Donald Trump? Trump’s boy Rudy? She ain’t sayin’ nothin’ that ain’t true.”

Here’s part of what Thunberg said to the U.N. crowd:

People are dying, entire ecosystems are collapsing. We are at the beginning of a mass extinction and all you can talk about is money and fairy tales of eternal economic growth. How dare you!

To call Thunberg rude would be an understatement, but so what? This is no time to be polite, because the powers-that-be — especially in the three worst-polluting countries, the U.S, China and India — keep pretending half-measures will solve the climate problem.

“She’s like Joan of Arc,” Swamp Rabbit said. “I’ll bet Joanie had Asperger’s, too.”

She is not like Joan of Arc, I told him. She’s like the humanoid visitor from outer space in The Day the Earth Stood Still (1951), a classic sci-fi movie that seems to get better with each passing year.

The humanoid’s name is Klaatu, as most movie fans know. He looks like he could have been David Bowie’s father. At the end of the movie, he warns a bunch of world leaders that “Earth will be eliminated” unless humans start behaving themselves and don’t try to wreck the rest of the universe with their nukes and other weapons.

But Thunberg’s concern isn’t about protecting outer space from humans; it’s about saving humans from themselves. More accurately, about saving young people and future generations from the generation that’s in charge now. She speaks to the Trumps of the world as if they are a separate, hostile species, intent on destroying the world even as they pay lip service to the idea of cleaning it up.

“Just like I said,” Swamp Rabbit said, interrupting my lecture. “She ain’t sayin’ nothin’ that ain’t true.”