The Team B player can't go low (it was a kick down). He has a guy who is trying to get in position to make a play on the onside kick and he is going to keep him from getting in that position. The kicker, who apparently thinks he is back on the soccer field "protecting the ball", got blown up due to his own lack of preparedness. If you judge the Team B player used his helmet in the hit, then it has to be flagged. Agree 100%. But I also know that helmets hit each other and hit other body parts just by the nature of the game at times.