I have no issue with people thinking there is referee bias because clearly there is. But this nonsense (and it IS nonsense) that any time we lose it must be due to some vast conspiracy does none of us any good. Officials make bad calls and miss obvious calls, every referee does it every single game - without fail. It doesn't mean the game is rigged.
Some referees take issue with the way certain players play the game and they watch for certain actions which can lead to poor results for the team that person plays on. And that's not even bias, it's decision making influenced by experience. But yes, on top of that, there is real bias in the game. And sometimes it impacts the final outcome. But the vast majority of time, IMO, it's neither agenda based nor consequential.
Years ago I'd just smile when I heard the latest conspiracy theory, I always considered them and the purveyors of such as harmless. The last few years have forced many of us to stare into the inescapable truth that conspiracy theories, all of them, are harmful, sometimes to the extreme.