Whenever there's a game where even 60% of the calls and most notably, a handful of important ones, go in favor of one team or the other, talk then becomes dominated by how the result was "fixed", how the administrators of a sport have determined that one team will lose and that another will win, based perhaps on region, perhaps on overall popularity or perhaps that somebody somewhere has just crapped out.
Sometimes, like the 1972 Olympic basketball finals, where one call completely changes the result of the game or other instances where players and/or coaches have thrown matches, these accusations have some merit. However, most of the time, as it is in life, mistakes are just that, mistakes.
To accurately "fix" a match, when it is so full of various twists and turns, would be exceedingly difficult, especially considering that if any part of it would come to light, that the validity of the sporting organization of itself would be immediately at threat. As much control as an official has, they cannot make a player score purely by influence alone. In cases where an official appears to be favoring a team, it is far more likely that the official is merely incompetent and if one team is forcing the action, those mistakes will be amplified to one side or another -- for example, if a team is constantly defending, either the official will call too many or not enough fouls and there will not be enough incidents of the overwhelmed team attacking to balance things out.
Why then, is it necessary to assign some sort of agency?
Or more importantly, as a friend likes to ask, "Who benefits from this narrative?"
The answer seems to be that people are more comfortable with the concept of malice as opposed to incompetence. Given a choice between a world where shadowy figures exert control through hidden measures and one where we are ground in our myopia between the gears of Destiny and Fate, people will go for the former. It at least allows for a situation where somebody is in control, even if they turn out to be Evil.
(It should be noted that one kind of conspiracy by the higher-ups is possible, in that by assigning an official who is known to be incompetent, it is likely that certain results will occur. This is analogous to the difference between saying that 9/11 was an inside job and that the U.S. Administration knowingly turned a blind eye to the possibility of an attack.)