My speculative theory is that they don't want to interrupt the flow of the game "unnecessarily". I mean, in the NBA the ref could blow the whistle on every possession if he or she chose to enforce the rules strictly at all times. Any NBA ref who did so would quickly be looking for a new job. NBA refs are exercising a tremendous amount of discretion at all times. If the ref has a string of plays where one team's fans think they repeatedly used that discretionary responsibility poorly, that is when I think those fans get upset. The NBA is entertainment so games are officiated differently than College or High School. It has to be. Echoing again what Dviss said: The worst mistake (IMO) NBA refs make is when they call stuff they didn't see, usually because they weren't in the proper position, or they miss something because they were ball watching. But the not calling every foul at the basket if the ball goes in, yeah that seems like standard operating procedure, depending somewhat on a player's "star" status.