I think there are some unwritten rules to try to keep the games going and entertaining, which can have side effects on winning for specific fans. Can't call a foul every play, so it is considered better to help the teams who are down deep, especially if they are the home team.
However, national TV deals and League Pass are changing this as every call can be video replayed by everyone worldwide. Therefore, over time the calls will need to trend toward fair, or there would be backlash.
So generally I think calls are fair, and just spicy enough with non calls or controversy to add to the overall entertainment (like two FT for Iggy at GS OKC game....boy that added drama to end of a great game, knowing Finals MVP, 65% shooter had game on the line). So I think that calls that could go either way tend to get called in a way the tends to reward the team the refs think deserves an advantage. That call rewarded GS hustle, added drama and was legit, so it gets called. Earlier contact on a lot Of warriors paint finishes were no calls. I think they were no-calls because they wanted the play to flow, the finishes were not super athletic, and that the refs felt the warriors should have been able to finish with that level of contact (in the refs minds). Some brush calls were called on warriors, after Westbrook make brilliant moves, when OKC was playing well, so I suspect the refs wanted to reward his athleticism and felt OKC deserved to preserve their lead. So I think the drive entries to the paint, that have good moves, get more calls than passing entries with a forced move to the rim. If the warriors hadn't made a spectacular steal... say they were inbounding with a few sec left, I don't think it is a call for Iggy. Just my interpretation of the calls/non calls. As a warriors fan I was mad at the non calls I thought we deserved, but I am biased.