Even if there was contact and even if it was a foul, if you read the wording of the law there was still simulation.
The decision making panel consists of an ex player, an ex official, & an ex coach who all see the evidence independently. There has to be a unanimous decision to make a charge.
If there had been contact, it would have been a foul, & DG wouldn't have been charged.
I'm also not sure that fans understand, that the simulation accusation is conditional on the award of a penalty or to get another player sent off. Diving that doesn't result in either of the above is not subjected to the ruling. So,(for example) had the incident happened outside of the penalty area, & we had scored from the resultant free kick, the result would have been the same, but DG couldn't be charged under the ruling.