Great post. Low level corruption exists in most major organisations. It can be as mundane as a boss turning a blind eye to expenses fiddling by one of his best workers or as serious as police officers turning a blind eye to one of their pals who is a murderer or a rapist. As many have said it is rarely about cash in brown envelopes.
There is an institutional bias in the media and the PL towards the bigger commercially valuable clubs and MUFC are still the main global cash cow for the PL. Without the PL PGMOL can't exist.
We don't know what motives Atwell had but I believe his decision was affected by the peer group pressure within his own organisation. I will never believe it was an "honest mistake" because he overuled someone who had a better view than him and made no attempt to check the replay. Many goals have been disallowed because an offside player who hasn't touched the ball blocks the goalkeeper's view and they are always checked by VAR. This decision can't be compared to other bad VAR decisons. It was not a difficult decision to make.
I think this is what we have with Attwell and maybe a few others like him, perfectly encaptulated by the phrase coined by
@LongsightM13, 'go along to get along'.
I very much doubt that the corruption in the PL is the brown envelope type, as is commonly put forward on here. It is much more subtle, and maybe even subconscious in the minds of the referee. We have seen things like Ferguson presenting Webb with a United shirt with his name on it, presumably at Webb's retirement. We saw Ferguson laughing and joking with Clattenburg, minutes before an FA Cup final, followed by United getting all the favourable decisions and a win against Palace. Clattenburg again, going on holiday with the Liverpool team, so he could explain the law changes to them, then favouring them in the following season. Scudamore saying that the league needs a strong United. Nothing is ever said or done about it.
Attwell is a weak individual, who is toeing the line giving the decisions he knows will be favourable to his bosses, and will prolong his lucrative career. Disallowing a United goal isn't a career enhancing decision, and isn't done lightly by referees or linesman. They don't need to have received a secret payment to remind them of this. When given a choice, United and Liverpool will nearly always get the benefit of the doubt.
I don't think we are counted as a big club against lower opposition, although their fans may dispute this. But it's always the less glamorous clubs that get the worst end of the stick. Look at Wolves last week. Two highly contentious decisions going against them. Remember that goal by Everton, deflected in off Maguire, but disallowed because Gordon was in an offside position (even though he didn't touch the ball) - very similar to the Salah goal.
Could it be described as institutional bias?