Standing over someone taunting them is often, actually, the reason a call is made... When you walk away you're giving them the chance to get up, and you can continue your chest-pounding without much of a second look. But standing over them generally is more likely to start a scuffle.
Also, the most likely reason for the call early is to "cut the crap" early so nothing escalates. The officials were ruling a monday night game on national TV, between two heated rivals on a normal night, but also on a night where the one rival's old QB is now on the opposite team. The early call made sense, trying to reign everyone in from stupidity early so it doesn't get out of hand later. They even do that at the high school level if they think the game's got a chance of getting more ugly than a taunt, hoping to stop it before it starts.
I don't remember the call that well, but it was maybe a little abrupt. Still if he was over the guy, that's usually the catalyst for the ref to call it. Did the calls continue all night like that or no? I forget now, but I don't recall another one.