Probably because players are either coached or just pick up from more experienced teammates that they are expected to dispute virtually every decision the referee ever gives against them.
It’s not because they hope to change the referee’s mind. It’s to try and put doubt in his mind that he’s made the wrong decision.
And not a single manager will ever call it out because he fears it would give the opponents a slight edge. They prefer to put as much pressure as possible on the officials and then call them out when they think they’ve been hard done to.
You end up with a trainer running on the pitch to treat an injured player, that the manager knows isn’t really injured and instead of blaming the player, sacks the trainer for her naivety.
Having said all that, on the odd occasion when a player is seriously injured, you do normally see human nature kick in and players from both sides showing immediate concern.
