During de Blasio’s frigid 2014 inauguration ceremony, Bloomberg sat in the audience grimacing as de Blasio and his hand-picked participants laced into the former mayor’s record, his “plantation called New York,” and the “Dickensian” justice system wrought by Bloomberg’s use of stop-and-frisk policing.

The hard feelings toward Bloomberg purportedly date back to de Blasio’s days as the city’s public advocate and council member, when positioning himself against Bloomberg had tremendous political upside: It is how he emerged victorious from a tough Democratic primary in 2013.

“There’s a natural adversarial role there that’s already been baked in,” said former de Blasio adviser Rebecca Kirszner Katz, now a consultant to other progressive Democrats.

People close to the mayor say de Blasio’s crusade against the Bloomberg presidential campaign is in fact rooted in strategy. It presents an opportunity to reassert why New Yorkers elected him in the first place, to recapture some bit of that 2013 energy that swept him into office.

That argument resonates with Christina Greer, a Fordham University political science professor.

“Bloomberg entering the race actually helps de Blasio’s legacy, because it reminds a certain segment of New Yorkers why de Blasio was so attractive in 2013,” Greer said.

But Jon Paul Lupo, who worked on de Blasio's presidential bid and now consults for his political action committee, says there’s a more straightforward explanation.

"As his successor, Mayor de Blasio has a unique perspective on Mayor Bloomberg's legacy and you and many of your colleagues have asked his opinion, which he is happy to share. This is a fight for the heart and soul of the Democratic Party and he believes a true progressive Democrat is best positioned to win," Lupo said.

If it all seems just a bit too emotional, his current and former advisers say, it’s because de Blasio is human — and it’s hard for him to hear folks lavish accolades on Bloomberg, a man de Blasio thinks has received undeserved praise.

“I think a lot of media outlets were literally worried he might buy them some day,” said de Blasio, echoing a specious contention from Bernie Sanders speechwriter David Sirota when Bloomberg entered the race. “And I think a lot of the leaders in those media outlets did not want to make waves or alienate him.”

Underscoring de Blasio’s frustration, advisers note that Bloomberg left New York City on many a weekend to golf in Bermuda , and then imperiously refused to say where he was. Yet he is depicted as a hard-working manager.

De Blasio might regularly arrive late to work, but he’s known to work into the night — still, the press calls him lazy. The media acknowledges de Blasio’s universal pre-kindergarten is a success, but little else. Bloomberg’s role in the deterioration of New York City’s public housing and the conditions in city jails gets little attention. Yet de Blasio wilts in the media’s glare.