You're not, they do.
There might be an "All Blacks" effect. New Zealand are always the best team in rugby so people, including referees, expect that they will win. Sub consciously refs give them more decisions as a result of this bias. It could be the same with united, they are the biggest club, the most successful and the bias towards them when it comes to refereeing decisions over the years is unarguable. They get the decisions because they are the big boys.