People's reputation or alleged reputation precedes them unfortunately. Refs and the FA should do more to factor this out, but in practice that doesn't happen. The press and pundits are complicit in characterising people that way as well.
So you get someone like Payet for W.Ham who is a serious cheat and a serial diving offender, but that get's overlooked by pundits and the press who are falling over themselves to talk him up. With Jose, the press do have a different tone with him than for any of the other "big" Premier League managers. Coupled with the fact that he's at United and he will be under more scrutiny and in all likelihood judged that bit harsher when it comes to FA punishments. Though I'm not one for FA conspiracies really, I think it's inconsistencies are down to it not being fit to govern the game full stop.
The misbehaviour of managers is a weird one as well, in that it does really add to the entertainment, and the FA, Sky etc.. must appreciate this. Certainly more so than the players, they're there to play and that's their bit. With managers, the bigger the character, the bigger the draw.
SAF would be a great example, I was lucky enough to meet him very informally & he was really charming, not at all as he was often characterised.