I can't claim that all NBA games are completely fixed as far as outcome, but based on things such as Tim Donaghy, the 2002 Kings-Lakers series, and the fourth quarter of Game 7 of the 2010 Finals, I think it's obvious that there are 1) certain outcomes the league prefers, and 2) some biases at work that exceed the "normal" amount of human bias.
For example, we all know that officials see things differently based on where they're standing on the court—maybe there wasn't a foul, but from one official's angle it looked like a foul. That's normal; that's understandable. We're all human, right? We all have limitations.
But another aspect of being human is that we are prone to grudges, even unconscious ones, so I have no problem believing, for example, that Official X has it out for Player X.
And I don't know where the idea of "superstars get more calls" originated—has the league sent a private memo to all officials to call things differently for superstars? Or do officials just presume that the league wants preferential treatment for superstars? Or is it something else?—but whatever the origin, I think it's undeniable that officials routinely practice that concept.
Maybe some officials try to balance things out with "makeup" calls, but I also know that the final foul count for any game doesn't always tell the whole story—that is, just because each team was called for 20 fouls doesn't mean that the game was fairly officiated. What if one team deserved all 20 of its fouls but the other team deserved only 10? Or what if one team deserved all 20 but really should've been called for 40?
This is a topic where we can really get in the weeds, but generally speaking, I think it's true that officials often have more influence on the outcome of a game or series than they should.