Nobody ever accused LeBron of joining the Heat, because he couldn't beat the Heat. LeBron was leading a 66 win Cavs team with Mo Williams as his 2nd best player. The 4 years prior to LeBron joining the Heat that team managed to win: 44 wins, 15 wins, 43 wins and 47 wins. They hadn't gotten out of the 1st round in 4 years. They also had to give away Michael Beasley (their former #2 pick) for a 2nd rounder despite the fact he had just put up averages of 15 points and 6 rebounds - they did that just to make cap space. Would be the equivalent of us giving away Marcus Smart for a 2nd rounder just to make cap space.
But if Durant joins the Warriors (as it's starting to seem more and more likely from "experts"), they will absolutely accuse him of joining the team he couldn't beat. Like if Jordan had said "no mas" and joined the Pistons after years of abuse from them. Durant will be seen as pathetic. They will destroy him. Even if he has a great season and helps them win a championship - the damage will be done. Steph will get the credit for the title.
I wouldn't say that they're similar situations at all. The Pistons beat Jordan 3 years in a row, whereas this past Western Conference Finals was Durant's first series against Golden State, I believe. Of course, Jordan also never got up on the Pistons 3-1 and still lost, lol

. I kind of get what you're saying, but the sample size is too small, for me, if that makes any sense.