The thing of it is, John Tavares was about to stay. When Lou Lamoriello was hired to run the operation and soon after hired Barry Trotz to take over behind the bench, No. 91 was prepared to forfeit a shot at free agency that was just over a week away, an individual close to Tavares told The Post.

Blind loyalty? Maybe. But Tavares had eyes for the new regime. After years of quirky ownership/front-office behavior and tyros behind the bench, Lamoriello and Trotz came with the kind of quirks reflecting off the diamonds in their four combined Stanley Cup rings.

He wanted to believe in the future — on Long Island — so much so that he was prepared to sign after going through the entire 2017-18 season without an extension. He was that committed.

But saner heads prevailed. Agent Pat Brisson of CAA urged Tavares to at least meet with teams during the interview period and listen to their pitches. And that is exactly what the franchise’s co-No. 1 non-dynasty player (with Pat LaFontaine) did.

And that is when he fell in love all over again. Fell in love with the concept of going back home again, to Toronto, where he would play for the team he rooted for as a youngster. Fell in love after being swept off his feet by the presentation offered by Toronto general manager Kyle Dubas and orchestrated by club president Brendan Shanahan.

So he left one home for another, portrayed as a conquering hero up north and castigated as lower and less redeemable than Michael Cohen in the burgh where he’d been revered since joining the Islanders in 2009 as the first-overall draft pick. He was a liar! He was a fraud! He was in it for himself!

Hey, where do you think that Republican came up with his “Liar, Liar, Pants on Fire” routine, anyway?

“The funny thing about that is that I have never played with anyone who did so much behind the scenes on behalf of his teammates and the organization,” Ryan Strome, a teammate for four years and a close friend, told The Post earlier this week. “Just little things like organizing dinners, making sure we were in the proper hotels, setting things up for wives, girlfriends and families. He looked after all of those things, all the time.

“In it for himself? That’s pretty funny.”

It was, however, anything but a laughing matter as Tavares returns to Long Island and to the Coliseum wearing the Leaf logo for the first time on Thursday night. A demonstration of rage was expected from fans who have been stoking a narrative of betrayal since July 1. Of course, If Artemi Panarin chooses to sign with the Islanders as a free agent this coming summer, he would be hailed. In Columbus, of course, he would be a bum.

That’s the way it works with fans, without whom there would be no Islanders, no NHL, no pro sports leagues and no writers to cover the leagues and teams and players. Thinking rationally generally does not get you a seat at the table.

But here is the thing. The moment Tavares decided to move on, the Islanders moved on, too. If Lamoriello has a list of commandments, the one about the logo on the front of the uniform being more important than the name on the back is either No. 1 or No. 2, depending upon where you put, get a haircut and a shave.

That is what the Islanders have done, this team considered perhaps not even the equal of the Rangers at the start of camp entering Thursday’s confrontation six points clear of a playoff spot and tied with the Caps (with two games in hand) for first place in the Metro. They were, in fact, only three points off the pace set by mighty Toronto, for whom Tavares has scored 36 goals, best on the Buds and tied for fourth best in the NHL.

In a live-and-let live world, that should be good enough for just about anyone. Pardon me, I forgot this is the real world. So the heaping scorn and thunderous boos are sure to rain on Tavares’ parade, just as they did on Wayne Gretzky, and viciously, in St. Louis the night of Feb. 13, 1997, when No. 99 showed up as a Ranger after leaving the Blues as a free agent the previous summer.

Gretzky and Tavares.

What a couple of lowlifes.