That expression, “You can’t make it up”? Well, you can make it up. Believing it is an entirely different matter.

Ignorance is bliss, but feigning ignorance relies on those stupid enough to believe it. Thus, leave it to the Mets, with MLB’s approval, to have this week enacted the preposterous.

They hired as their general manager Brodie Van Wagenen, 17 years a players’ agent, who now vows to “recuse himself” — remove himself — from all dealings concerning recent clients Noah Syndergaard and Jacob deGrom.

In other words, the Mets have hired a GM who, when it most counts, vows not to get involved.

Exactly how is that going to work? When, for example, deGrom’s future is discussed and determined, Van Wagenen will leave the room or, to be extra cautious, leave the country? Or will that determination be a quick process completed while the new GM, with no say whatsoever, is out to lunch?

His input won’t be solicited, known, weighed or, at the very least, fully suspected? Or are we to believe that the Mets hired a GM whom they’ll gag and handcuff when it’s time to make big decisions? Van Wagenen seems too smart to not know better. But we’re not?

Jeff Wilpon explained deGrom: “We have to have some others responsible for doing the actual contract, right now.”

Others? How about their GM? The “actual” contract? Does that mean Van Wagenen can work on the virtual ones for his very recent — as in last week — former clients, including Yoenis Cespedes (sold to the Mets for four years, $110 million and who has provided next to nothing)?

To acknowledge a conflict of interest is not to avoid or void one. For a GM to claim that he’ll recuse himself from significant negotiations and decisions sounds both nice and nuts. How is that done? Will he work with hand signs or winks and nods?

More significantly, why? Why would the Mets hire a GM who might not be able to play a role in whether the club signs or re-signs his many former clients?

Unless, of course, our ignorance is their bliss. And the Mets’ soulful claims that they took preemptive care to be above suspicion of duplicity are insulting.

Van Wagenen doesn’t have an intimate business and personal relationship with any in his large agency that now will rep his former players in dealing with the Mets?

Does he have a list of his recent players he’s now disqualified from discussing as the Mets’ GM? If so, for the sake of “transparency” — once known as the truth — may we see it? Or is his confidential knowledge both for sale and transferable?

But MLB has given the Mets the coincidental opportunity to have their new GM collude with himself, by himself, on behalf of the flailing but biggest TV money-market Mets.

Rob Manfred, the latest team owners’ CFO posed as commissioner, was Bud Selig’s legal beagle. He should know this arranged marriage wouldn’t pass the stink test in law school day 1, hour 1.

Or would Manfred go to court knowing that the judge was a recent — as in last week — and highly successful business partner of his client’s opponent? But as long as His Honor claims he’ll render his verdict, no strings attached, that meets Manfred’s approval? Fat chance.

When this deal made it to Manfred’s desk, he should have immediately nailed it with the John McEnroe red-ink pad “You cannot be serious!” stamp.

The best of team operations wouldn’t scheme such absurd, malodorous entanglements. Yet the Mets, among the worst, are all in. Cutting edge!

But if MLB, under Selig, didn’t demand the liquidation of the Wilpon family’s financially reckless Mets ownership for twice proving easy prey for Ponzi schemers, why not? Play ball, or whatever it’s now called.

MLB’s silence on crass Cora speaks volumes

Class Dismissed: That those who know plain rights from wrongs and are in a position to make a difference — commissioners, media — instead avoid the scenes of the crimes against civility is a significant reason why our sports increasingly resemble untreated sewage.

Conspicuously bad winners are now as common as sore losers.

Wednesday, as part of a Red Sox victory parade in Boston attended by roughly 750,000 — and of all ages — manager Alex Cora took the microphone and in a classless ambush, attacked the weeks-ago vanquished Yankees with a vulgarity for fellatio. The crowd, naturally, cheered its approval.

But this is where we are. Rob Manfred, a panderer who pretends to believe that your kids — not his — would enjoy baseball if they acceded to TV ads encouraging them to acts of in-game immodesty — even if the ads appear at midnight — should have immediately and publicly condemned Cora for his indefensible public conduct.

Unless, of course, Manfred was good with it. If so, he should have made that equally clear.

But along with the commissioner’s, the media’s right-minded outrage has been silenced as a matter of illogical fear — the fear of being mocked by the mostly young and desensitized, desensitized by insidious marketing design.

Those soul-for-sale MLB ads promoting selfish play by kids contain a background mockery of those heard urging professionalism — say, running to first base — from professionals.

This NFL season began with the latest in a series of Roger Goodell-indulged lewd touchdown “celebrations.” In Week 1 against the Raiders, Rams cornerback Marcus Peters returned an interception, then merrily grabbed his genitals.

Peters was quietly fined $13,000 but said, “It was worth it.” His coach, Sean McVay, gave it his approval as “a light-hearted moment,” the media gave it brief but nonjudgmental attention and Goodell returned to pretending that he never said “PSLs are good investments.”

The rush to promote antisocial and, forgive the antiquity, unsportsmanlike behavior shows up in all forms and in all planned but unopposed ways.

Sunday, late in Fox’s Packers-Rams, Green Bay safety Jermaine Whitehead was injured. As he limped off the field, he was mocked by the public address system, which played “Hit the Road, Jack.” The man was hurt, hobbled. Hilarious.

All-or-nothing Dodgers need better strategy

The Fallen Classic: With baseball in systemic free fall, let the record show that the last six Dodger outs in this World Series came on strikeouts, all of them of batters swinging from their heels, trying to hit home runs, down four, rather than reach base.

The Dodgers lost this World Series the way they lost last year’s: Hit a home run or strike out trying. This time was worse. The Dodgers totaled 34 hits to 56 strikeouts. Until 10 years ago, World Series hits regularly far surpassed strikeouts.

But a few Dodgers did run to first base.