This is one of the most ridculous statements I've heard yet. This is an adult at a kids sporting event for godsakes! It would be unreasonable conduct at any event. Do you also give warnings to all the coaches and players before you issue fouls because maybe they didn't know it was illegal?? Do you not eject a kid for a flagrant foul because maybe they didn't know they couldn't bodyslam an airborne shooter? Maybe you just inform him he can't do that again because an ejection might be too embarrassing for his fragile ego?
The only thing that jkjennings should have done differently was call management and have them eject this azzhole themselves. In no case should conduct like this, especially by a parent, be tolerated.