Probably because they are used to getting decisions against them when they do something.
All these bullshit calls we've had will have an effect.
Sterling looked liked he'd finally shaken the last sandbag off his back when he scored only to have the 0.5 second obligatory LiVARpool decision take it off it.
About time the PL fronted up and admitted they want WWE entertainment over the actual rules of the game.
I can see a F1 style stitch up on us to give the cultists and their fawning media chums the result they wanted. They'll drown in their jizz if they can manufacture a moment which takes Sergio's goals from the zenith of PL finishes.