It's not about NBA but didn't Diego Maradona said something similar? - Ban bookmakers and you'll see a real football.
Correct me if I'm wrong but I remember a similar statement from someone but I don't know who and how they said it in English, it's my interpretation.

Basketball is the most famous sport after soccer, NBA is one of the richest league in the world, richer than soccer leagues. I'd say that the NBA is not rigged but sometimes referees are rigged. NBA is too big to rig, no profit worth the potential loss that it will generate if they rig the game or anyone inside the NBA leaks the information. I often bet on soccer matches and I know that there are cases when referee will be on one team's side, so I either bet on that team or I avoid the match.