That was my impression as well. The father didn't start a fight with a gang, he just yelled at two guys when one of them groped his 12 year old daughter's butt. I don't know if I would have had the restraint to only yell at them.
If someone groped my daughter's butt in the middle of a public amusement park, it would never occur to me to stop and think, "Gee, I'd better not say anything or this guy might call a bunch of his friends on his cell phone."
If I were not packing, I'd have herded my wife and/or daughter away and just tried to get out of there. Did you see the mug shots of those dudes? Best not to mess with them. If I saw a dude or two like those guys approaching me, I'd be reaching into my pocket getting ready to do a fast-draw. If I didn't have a weapon, I'd consider myself outnumbered and out gunned and would decide discretion was the better part of valor.