That is because the referees have full backing of the rugby union, and complete respect of the players. In Association football when a player is penalised he is too often inclined protest his innocence and argue with the referee as a spoilt child might in similar circumstances. When he realises that he is not going to get his own way, he will throw a tantrum, again the actions of a spoilt child.

In Rugby football the player will accept the decision of the referee like a mature reasonable adult, and even if the player believes he has been hard done by, certainly would not argue with the referee or throw a childish tantrum.

This is one of the reasons I rarely watch a game of the former these days but watch the latter whenever the opportunity offers, even if it is not 'my' team playing.

This behaviour difference is reflected amoung the supporters, which is why there never has been and I hope never will be a need to segregate supporters at a Rugby Match.