Now there are some other interesting comments that you bring up. The impression by administrators that Soccer is the sport with the most fouls, ejections and violence. Hmm, most fouls? I find that position difficult considering basketball gets 5 fouls before someone fouls out. Soccer only gets 2 before you are ejected so how can soccer have more fouls. As to ejections of course soccer has more ejections because they are allowed only 2 fouls. BTW in football you can commit as many fouls as you like until your coach pulls you out because your team lost so much yardage. As to the most violent I guess we need a definition of violence because football's very existence is predicated on violence.
IMO there is no reason for a fan to scream or yell insults or deragatory statements. However, I do feel it appropriate to disagree with calls. So yelling about your disapproval is very different then throwing defamatory statements. If I were to encounter such that I feared for my child on the field I would certainly make sure the administrators were aware of my concerns and the police were at the next game!
As to the apple not falling far from the tree please remember that in public high schools we do not choose who attends the school with our children. In most cases, I would interject when I see inappropriate behavior but there is a very fine line when it comes to disciplining others children. Then throw in the social issues at hand and (for lack of a better example) guns and the general public will shy away.
I have taught my kids the old cliche of act like you have been there before. So there is no excuse for players to "snap". I don't snap in my place of work, worship or the local grocery store so what makes it acceptable on the soccer field? Ignorance is bliss so ignore them!