The reality is, referees are cowards, they hate getting abuse. So when they make a contentious decisions against one of the media's preferred teams, the media all leap on them, show the "mistake" (it's now definitely a mistake as they've lined up enough pundits to say it is) on a loop and bang on about how hard done to the team are. The referee gets a load of shit over it and all the other referees see what happens if they have the audacity to give a decision against that team. Naturally, next time an incident happens involving that team, the referee subconsciously errs on the side of self preservation, if he's not entirely sure then he knows he'll get a lot less abuse if he gives it the way of the media backed team. The clearest example of this Ive ever seen is when Anthony Taylor fucking apologised to Mourinho for booking one of his players for diving. Have you ever heard of that happening before or since?
Then the reverse happens when it's someone like us, who the media won't make a big deal over a bad decision against us, they will probably let the referee off or even claim it's good that the referees are finally clamping down on this sort of thing (only to never see that incident "clamped down" on again for any other team). The referees get away with it and again subconsciously know next time they are involved in a decision involving us that it's ok to penalise us as even if they are wrong they won't come under much fire.
It's just pure cowardice and self preservation and it's the same in all leagues. The media decide who it is ok and not ok to give decisions against and it takes a very strong referee to not be influenced by that.