Man, people are unbelievable sometimes.

The reactions I’ve seen to the Knicks’ agreement to hire coach Mike D’Antoni away from Phoenix are absolutely staggering in their negativity.

So, let me see if I’ve got this straight: The Knicks hired a guy who took over a 29-win team and won 62, 54, 61, and 55 games in the four years that followed — and people have a problem with this?

Apparently so. It seems D’Antoni has been coaching for all of four years and hasn’t won a championship yet, which obviously makes him flawed — irretrievably so. People have it in their heads that slow-paced, defensive teams win championships, and even though you can prove this isn’t true relatively easily (it’s more like “awesomely talented teams win championships”), the stereotype has some folks down on D’Antoni even before he’s coached a game.

Which is why I have to remind people that the fraternity of coaches who have won a championship is incredibly small — doubly so since one man hoarded nine of them and another one four in the past 15 years, and both of those gentlemen have essentially been appointed coach for life by their respective franchises.

Let me spin this another way for all the armchair general managers out there: Whom were you hoping they would hire? As I mentioned above, Phil Jackson isn’t leaving the Kobe Show for these clowns. Gregg Popovich isn’t waving goodbye to Tim Duncan so he can work with Zach Randolph. Those two account for 13 of the past 17 championship wins by themselves.

As for the others? Pat Riley has grown weary of coaching, at least until he has a title contender again. Ditto for Rudy Tomjanovich, who is plenty happy scouting for the Lakers. And Chuck Daly retired a long time ago.

And that, my friends, is a comprehensive list of the coaches who have won championships in the past two decades. None of them have any interest whatsoever in coming to work for the Knicks.

Oh, actually, I left one name out. There is somebody who won a championship and might even be available, given that he started a new job a few weeks ago and is probably already looking for his next one.

His name is Larry Brown. I’ll pass, thanks.

Presuming the Knicks were picking from the “coaches without championships” list, D’Antoni was far and away the best candidate available. He’s been to two conference finals in four years, and he could make a strong case that, if not for untimely injuries (Joe Johnson in 2005) or suspensions (Amare Stoudemire in 2007), he’d be on the list of coaches with rings.

But there’s more, the critics say; yet another good reason not to hire D’Antoni: His style is a bad fit for the roster.

Gee, ya think so, Einstein? And when you made your list of coaches for whom this roster was a good fit, how many names were on it?

The Knicks have one of the most mismatched, ill-fitting groups of parts ever assembled. Of course the roster is a bad fit for the new coach.

So here’s another news flash for the rocket scientists in the audience: The Knicks are going to get rid of nearly everybody on the roster within the next two years. The new general manager, Donnie Walsh, was going to do that regardless of whether he hired D’Antoni, Mark Jackson, or Paris Hilton.

Thus, the issues with the current roster are at best temporal and, in the Knicks’ rebuilding time frame, irrelevant. Sure, you can complain about D’Antoni being a bad fit for Stephon Marbury — just as soon as you find a coach who is a good fit for Stephon Marbury. And since Marbury has a 0% chance of still being on the Knicks 12 months from now, it doesn’t matter anyway.

You can complain about D’Antoni’s run-and-gun, 3-point-shooting, Euro-influenced style as a poor fit for a team that started two huge, plodding post players — just as soon as you find another recent team that succeeded by starting two huge, plodding post players.

Besides, a few players on the roster are likely to perform better under D’Antoni. Nate Robinson, David Lee, and Renaldo Balkman all are much more effective playing up-tempo, but they rarely got the opportunity under Thomas because he was so focused on hammering it inside.

And then there’s Wilson Chandler, the eye-opener from the Knicks’ final two weeks of the season, who should take on a much bigger role next season. Thomas used him exclusively as a small forward, but don’t be surprised if his main role next year is as a power forward in a “small-ball” arrangement similar to the one D’Antoni created for the 2006 Most Improved Player, Boris Diaw, in Phoenix.

Also, here’s one for you: How about Randolph? He’s an offensive force who can post up or stroke it from 20, and his defensive shortcomings might be less obvious if the Knicks’ high-activity guys (Lee, Balkman, Chandler) are getting lots of burn. He’s not the high-flying freak that Stoudemire was for his Suns. But if Randolph stays in New York, don’t be surprised if D’Antoni carves out a similar role for him.

Regardless, part of Walsh’s mandate now is to bring in the types of players who can thrive in D’Antoni’s system. It shouldn’t be real hard, actually. Everybody wants to play in New York, and everybody wants to play for D’Antoni. The combination of those two factors should make the Knicks an attractive free agent destination.

In fact, one prospective local free agent has already taken notice, as Bostjan Nachbar, who played for D’Antoni in Europe, told the Newark Star-Ledger yesterday.

“Who wouldn’t want to play for Mike?” he said. “He shows tremendous trust in his players, and I guess I fit perfectly into his system and his vision.”

Does D’Antoni have some weaknesses? Sure. He made a couple tactical errors in the Suns’ loss to the Spurs in the first round of the playoffs this year, and his emphasis on offense does come at a defensive cost. He’s also sensitive to criticism and will need to develop a thick hide fast in the Big Apple.

But to say this is a bad hire because he hasn’t won a championship, or because the roster is a bad fit, is patently ridiculous. D’Antoni was clearly the best candidate available for the job, and that Walsh was able to hook him out of the Bulls’ hands is our first strong sign that the new Knicks regime will get this thing turned around sooner or later.

jhollinger@nysun.com