All human decisions are subject to bias.
It's one of the main reasons judges have to work to sentencing guidelines, otherwise some judges would give a first offender 18 months in gaol, and another set him/her free with a £50 fine. How hungry the judge was at time of sentencing can influence the degree of penalty.
All human decisions are made because somebody thought it was the right thing to do at the time. Bias does not come into it. If I decide to eat in McDonalds in Liverpool instead of KFC, then it doesn't mean I'm biased against KFC. I could happily eat in both, but I can only decide to eat in one at any given time, so the human decision I make has to be one or the other.
Since the game against Spurs ended, everyone who is someone has argued the toss over it. Players, pundits, managers, posters, administrators, and commentators. The one exception who hasn't had any chance to comment has been the ref. (and the officials at the game) He doesn't have an outlet and whatever he does say, would be ridiculed anyway.
Like all refs, Tierney gives decisions in our favour and sometimes decisions against us. If he was biased against us, he could easily have sent off Jota and Klopp, and nobody could argue if that's what happened. But he actually did Jürgen a favour by not dismissing him, and save him from another touchline ban. Other refs may not have been so lenient. Then Jürgen put his foot in it by attacking his integrity, and now we'll have to deal with the consequences.
There are two types of people in the world, amateurs and professionals. The amateur says something because he feels like it. The professional says something when it's in his best interests to. Jürgen is long enough in the game to know that whether it's England, Ecuador or Egypt, you do not attack a ref verbally or physically at any time. There is no excuse, blaming emotion is not a good enough defence unfortunately, and it's not the first time this year either. Whatever he thinks of the decisions made, as an official representative of the club, it's in his interests to behave in a responsible manner. Germans are admired and respected worldwide for their calm and restraint, not panicking or letting emotions cloud their judgement. So maybe the message will get through the second time around. It has to.
No matter how many times you say it, that decision to not give the neighbours a penalty against City did not cost us the title, any more than it cost them their place in the league. Stating otherwise is simply lieing. The league is decided over results across 38 games, not whether other teams in games we're not part of, (that may not even be scored) get penalties or not.
As for the British judicial system, bias or no bias, it's littered with wrong decisions and injustice. We know that a system that forces our brothers and sisters to wait 27 years in pain rather than the 27 hours they needed, just to state the bleeding obvious, is not a system that should be held up as a model of anything.