The logic is that in a running clock situation, it takes at least 10 seconds from the runner being down to the ready-for-play. Therefore, when the clock was stopped solely because of a reversed call, that 10 seconds needs to be run off in order to return the game to the state it would have been in had the call be made correctly in the first place.
Personally, I think NFL crews average less than 10 seconds from dead ball to RFP under these circumstances, but that's what it is. If he had been correctly ruled down in the field of play, the clock would have run out before the next snap could have occurred. This should be pretty uncontroversial.