They have an F1 style end of season, start of season referee briefing about what's allowed/not allowed. Their grievences are aired etc.... and then the season continues to be a circus as every other season before it.
I genuinely believe there's a collusion between clubs refs, and Sky to create the best "spectacle" possible, therefore some refereeing inconsistency is seen as desirable to generate outrage and drama. It also works perfectly as cover for favourable treatment to Man U, Liverpool, and to a much lesser extent, the other big 6 clubs. It's a bit like Jimmy Saville, prince Andrew, Eppstein etc., everyone knows, but no one talks about it.
The PL involves monsterous amounts of money and some very greedy corrupt people, no way they'll allow complete transparency and objecitivity, it robs them of their influence on things like relegation, top 4 etc.