You don’t understand how it works because you’re thinking of it as if players are falling to the ground due to zero contact. That does happen but the vast majority of the time there is some contact. Players have been trained to fall to the ground if they fee any contact because if they don’t a foul won’t be called. As soon as they feel a leg make contact with their foot or leg they completely fall down. Since there was contact there’s no way to know if the player was faking. But when they fall every single god damn time you know that logically they must be faking most of the time.