As one other poster stated rules are rules, but c'mon that was just an over zealous referee making that call. I have been a head referee for leagues from pee wee flag football all the way to the high school level for the last 3 years and I wouldn't have allowed my sideline referee throw out a teams star player for that minor of an infraction.
I had a game last year where I was the head ref and a team's star player kept taunting the opposing team's players and at one point started shouting profanities at them. I merely walked the player over to his coach and told the coach unless he wanted his player ejected he needed to get him under control. Well that player came out the next play and said another profanity, then the opposing coach said by the rules I had to eject that player. I asked that coach if he wanted me to decide the outcome of the game or if he wanted the players on the field to. The coach actually said he hadn't thought about it that way and said he respected that approach. Of course the same player did it a third time and I did eject him at that point.
I have seen other players grab refs and not get ejected for it. The thing none of us know is what Smith said to the ref, but even if he said hey you dummy that was a late hit, it shouldn't have gotten him ejected.