When Donald Trump slapped his name on the Kennedy Center, he was — rightfully — torn a new one.

His monster-sized ego is something to behold and, yes, to be criticized at times.

But this week another egomaniac unveiled his own monument. Let’s call it the “curious case of the disappearing gripe.”

Funny, though, how the media and the commentary class that’s so eager to declare an existential crisis over every move Trump makes suddenly find themselves out of righteous anger.

It’s simply true that, when Barack Obama enters the fray, these same whiners hit the Off switch for the outrage and the grievances they so eagerly and reflexively dish out for DJT.

Instead they offer tongue baths, back-rubs and praise. Nonstop praise, even as Obama introduced his bizarre monument to himself. On Thursday morning, the Obama Presidential Center was unveiled on the Chicago’s South Side with an A-list group of sycophants.

The $850 million dollar “Obamalisk,” as it’s been dubbed, stands in Chicago’s historic Jackson Park and can be best described as U-G-L-Y. It’s an obscene, Death Star-like eyesore in the Windy City that takes up land that was previously set aside for regular Chicagoans.

“Obama, of all people, should not be building a palace for himself, a fortress in the middle of a public park. It’s just contrary to what I thought he believed in,” renowned Chicago architect Grahm Balkany, a self-described progressive liberal, told The Post last year.

The Obama Foundation, on Instagram, wasted no time in patting 44 on the back: “We are bringing together some of today’s most prominent voices and global icons for the Obama Presidential Center Grand Opening Ceremony.”

The global icons include Bruce “No Kings” Springsteen, Eddie Vedder, John Legend, Common, Christina Aguilera, Jennifer Hudson, Bono and The Edge, and the Roots.

Stevie Wonder closed out the event with a rendition of “Higher Ground.” We’ll give him a break. He can’t see just how ridiculous the building is.

It’s not exactly a presidential library, but a museum — and a monument to ego.

Also unusual: No records from the Obama Administration will be stored on site in Chicago. No government archivists will be on hand from the National Archives and Records Administration (NARA) to help scholars research the Obama presidency. It is run privately by the nonprofit Obama Foundation instead of NARA.

“It would be good for the country, especially in these times, if a new national museum with a nonpartisan mission to inform and educate about the Obama era were opening this week,” Tim Naftali, former director of the Richard Nixon Presidential Library and Museum, told CNN.

But no mainstream media folks or preachy celebrities are calling this out. If Trump took a chunk of Central Park and built something like the Obamalisk, there would be riots.

When Trump said he was going to demolish the East Wing to create a ballroom for future administrations to enjoy, the left mourned it like they would a family member — even if they couldn’t locate it on a map or by sight.

“Top Chef” judge Tom Colicchio posted a photo in memoriam on X, writing, “My wife and I in the East Wing. I can’t believe it is gone.”  But the photo wasn’t in the East Wing. Colicchio just happened to be living in a perpetual state of TDS.

Indeed, this is why our country is divided. All that selective outrage is wearing thin.