There's some "interesting" reasoning going on here.
We expect great players to be extremely competitive. We expect them to desire, above all else, a championship.
We deride any star players we perceive to care more about other things -- money, endorsements, the love of casual fans, celebrity -- than winning.
We want great players to strive for greatness, to desire above all else to make history.
We want players, stars and otherwise, to demonstrate a willingness to sacrifice their own personal glory and prestige, even the admiration of fans and fellow players, in order to achieve historic greatness and multiple championships.
So ... Kevin Durant joins the Warriors and in so doing becomes part of arguably the greatest collection of talent on one team in the modern era of the NBA. Implicit in this decision is a willingness to subsume his own talent, his preferred style of ball-dominant play, to the needs of a team with multiple elite talents, at least to some extent. As a result, he now arguably has the best chance he's ever had in his career to win not just one ring, but multiple rings.
As a result, of course, he is a punk, a coward, a player taking the easy way out. We criticize him mercilessly. He is, somehow, the opposite of all that we supposedly want a great player to be.
Let me ask you guys and gals this:
If Durant had stayed in OKC, what do you think the odds would have been of that team winning a title in the next 4-5 years, while Durant is still in his prime? Do you think their chances in any given season would have ever been better than 10%?
Take into consideration the injury history of both Westbrook and Durant. Don't forget, either, that OKC had demonstrated an inability to keep star talent together long term due to financial constraints. Not to mention question's about Ibaka's age.
When I see this conversation I often think about guys like Charles Barkely, Karl Malone, and Patrick Ewing. Everybody agrees they were great players, but the dominant narrative of their careers, in retrospect, is that they were never able to overcome the superteams that dominated the league during their careers. None of them ever won a title.
I don't think it's so hard to imagine Durant following in their footsteps, losing year after year to the Warriors, the LeBrons, or perhaps, in later years, whatever the next superteam will be (the Wolves?). He was already weighed down by a reputation as a great, MVP caliber player who "couldn't close" in the playoffs.
If Durant spent the rest of his prime winning 50-60 games in the regular season but never making it past the Warriors or Cavs, and he ultimately failed to win a title, wouldn't he be looked at in the same way we now regard Barkley, Ewing, and Malone?
Without a doubt, Durant's glory would be greater if he had stayed in OKC and somehow managed to get past Golden State and beat the Cavs. But the much greater possibility is that the Thunder would continue to be an also-ran, even assuming their main guys stayed together and stayed on the court when it mattered most.
It seems to me many here are guilty of placing Durant in a bit of a catch-22. Chances are he would have drawn your criticism; it's just a matter of it coming now, after he joined the Warriors, or five to ten years from now, when it became clear he wasn't going to win a title with the Thunder despite well over a decade of trying to make it work, trusting in the flawed and stingy ownership of that franchise, and repeatedly falling short.
My guess is that if a year from now Durant has a ring on his finger and a Finals MVP trophy on his resume, he won't mind being regarded as a ringchasing villain. Much better than to be this generation's Barkley.
Sorry, Chuck.