The brains behind the Oakland Athletics are lauded for their savvy success on a low budget.

The innovators who took over the Tampa Bay Rays are cheered for turning around a franchise with frugal maneuvers.

The Boston Red Sox, who fired their manager after one bad year and unloaded expensive stars, are patted on the back by fans who haven’t lost faith.

Yet Jeffrey Loria is vilified as a crook and a liar for purging the payroll of his failed Marlins experiment.

What’s the difference? Why are baseball executives who win with small checkbooks called visionary geniuses while Loria, who won a World Series for South Florida, is an evil genius?

Loria’s critics have taken turns bashing his character with a bat since the trade with Toronto sent five Marlins out of town in exchange for mostly unproven prospects — three months after another chunk of the team was traded.

Players are not commodities in fans’ eyes. It has been an emotional parting, especially here, where baseball lovers have been jilted repeatedly.

The deal with the Blue Jays was approved by commissioner Bud Selig and has been almost universally received an A grade by baseball experts for its value, the business buzzword in sports. Shrewd move by president of baseball operations Larry Beinfest. Shortstop Adeiny Hechavarria should be even better than Hanley Ramirez, the superstar who stalled, or Jose Reyes, who had a good season in his brief Miami career but is always one swing away from another injury.

The young pitching talent is promising, and we all know how Heath Bell bombed and Josh Johnson fell short of expectations. The Marlins still have their farm-raised slugger Giancarlo Stanton, and eventually Logan Morrison will start hitting.

The Marlins are back to their old skinny but hungry ways. Beinfest acknowledged that at $34 million they are already near their payroll goal, which would make it the cheapest in baseball. They have an inexperienced, inexpensive manager in Mike Redmond after firing high-priced Ozzie Guillen.

But no one here is accepting this roster as a smart reset after an awful last-place finish with a $95 million payroll and splashy free agent signings. No one is giving Loria credit for doing what he said he would do in 2012.

Why? Because Loria and his associates have used up any shred of goodwill they had left, just as they did in Montreal. Red Sox fans trust their owners. Who can trust Loria’s motives after he promised he would spend to field a winning team once he got his longed-for ballpark?

He spent, the team failed, he’s blowing it up and trying again.

Seems logical, but everyone interprets his plan as diabolical. Loria’s worst mistake was mismanaging his credibility. He has none — and he misled free agents who signed multiyear contracts.

He and team president David Samson rubbed people the wrong way, and they didn’t try to correct it by building faith. They have been abrasive, secretive, condescending.

They do not want a loser. But they failed to show they care.

Many of us saw the stadium shell game for what it was from the outset. And we foresaw our political “leaders” falling for it. Now we’ve got a new $515 million stadium complex and fans who swear they are going to boycott games.

So where does this leave Loria, the 72-year-old art dealer who grew up in New York as a Yankees fan? Other than the loathing that generally doesn’t bother rich people or they wouldn’t have become rich in the first place, Loria has to be measured as a very successful pro sports franchise owner.