While poor sportsmanship should never happen, unfortunately it does on occasion. I recall BYU fans throwing things at officials on more than one occasion (football and basketball). It shouldn't happen.
I have no idea the details of the altercation (there seems to be very few that are public). If the situation is as you presented maybe a complete ban would be appropriate. But I'd be very surprised if the whole team, parents, admin, coaching staff, etc were all in on the cover-up and nobody was talking.