Is It Unsportsmanlike to Play Keep-Away Mockingly? A Ref's Dilemma in a Lopsided U14 Game

An assistant referee on a rec U14 soccer game describes a dominant team told to play for possession instead of piling on goals, then taunting the opponent with showboating like touching the ball with their knees before uncontested passes. The post asks fellow refs where the line is between sportsmanlike game management and unsportsmanlike conduct.