This is not an argument about whether the stoppage was good or not. It's against the notion that Rosenstricuk would have kept on attacking if the ref had not waved off the fight.
As you can see, Rosenstricuk was on the other side of cage with his back turned and hands down. He assumed the fight would have been stopped. In his mind, there was no reason to turn around. Thus if the fight wasn't stopped the four seconds would have ticked away without him facing his opponent. Even had he realized, I doubt he could have rushed across the cage and connected cleanly with Overeem in just four seconds. Rosenstricuk could have easily lost the fight.