I don't have a good grasp on all of the intricacies of the English media, but to me it seems like there is media bias against Arsenal (for whatever reason), which then bleeds into decisions made by on-field refs. For example, the media has pushed this "dark arts" narrative this year, which has seen us receive the most yellow cards for time wasting / delaying restart in the league. However, when we actually watch the games we see the same time wasting / delaying restart actions being used against us and often going unpunished.
Now if we want to get into Michael Oliver specifically, then here's the most clear evidence of bias you'll ever see/hear. He reffed our game vs City last year in which he self-admitted to not giving Kovacic a second yellow card because he didn't want to "ruin the game." Mind you that VAR also reviewed his first yellow card tackle for a straight red card, which would have been deserved, but Michael Oliver deemed it a yellow card and then refused to give a second yellow for another tackle 5mins later. Whereas in the game he reffed between us at the Etihad this year, he sent off Trossard for a time wasting / delaying restart second yellow card because Trossard tried to pass a ball to Martinelli half a second after his whistle. So apparently he doesn't mind "ruining the game" when it's at Arsenal's expense.