“Rainbow up” or lose your funding: That’s Mayor Bill de Blasio’s message to Carnegie Hall, the Metropolitan Museum of Art, the New York Aquarium and other cultural nonprofits.

Blas’ gripe: Whites make up about two-thirds of the staffs at these institutions, but only a third of the city’s population.

That’s not remotely a shock, nor is it any sign of privilege, oppression or exclusion — as is shown by the also-unsurprising fact that the overall arts workforce is 65 percent female and 8 percent disabled, with 15 percent identifying as gay, lesbian, bisexual or queer.

No matter: City Hall has been hectoring the nonprofits for years, ordering them to bean-count their workforces and to adopt “Diversity, Equity, and Inclusion” plans to address any un-PC results.

And this year the city Cultural Affairs Department laid down the law: “Institutions won’t receive their full funding without demonstrating their commitment to equity and inclusion.”

This is crazy. Just for starters, while cultural jobs carry some cachet, they’re not all that well-paid. That’s why parents all across America beg their kids to study something more practical in college. Some still follow their passions — especially those whose families have the resources to keep supporting them.

That alone seriously skews these institutions’ hiring pools. Are they to put hiring quotas ahead of their missions?

When it comes to the artists themselves, things are clearly changing: Ballet may well be the snootiest, whitest sector of the cultural world, yet it has ever-more superstars of color (decades before Misty Copeland, there was Edward Villella), and even growing numbers of black-majority corps de ballet.

Most important is that opportunity is equal when it comes to the public: Any New York child can walk into the Met for free and engage with the entire artistic heritage of all mankind.

The city’s cultural institutions are working. Blackmailing them into jumping through racial hoops is the worst kind of political power play.