Call me naive but I refuse to believe that referees do this stuff deliberately, I am more inclined to think its some sort of unconscious bias that leans them in the direction of favouring the RS in decisions that aren't 100% clear cut.
But then you get into the realms of playing 12 mins added time when only 7 had been put up on the board and you start to think woah.....one even two mins one that can be down to unconscious bias, but bit four or five.
It’s self preservation, if they weren’t perceived to get the rub of the green in Klopp’s day, or United didn’t in Ferguson’s, the manager would kick off a tabloid shitstorm about not getting a fair crack, blew thre seconds before a corner or whatever, and refs would give them some leeway to save themselves from being at the centre if a week-long whingeathon.
Of course when it works the other way, Tarkowski’s derby for instance, the likes of Slot still create a tabloid shitstorm and half the country starts to believe it.
In short, fuck them, mid table clubs are reffed to different standards to Cl ones unfortunately.