Unfortunately, Americans today live in a society that doesn't allow for provocation.
NO one should be allowed to say something like that about someone else without consequences. Unfortunately, the only avenue the mother has would be to file a police report (since parents are basically worthless nowadays and the boys parents would likely do nothing). Of course, we all know where that police report would end up - no where.
That leaves people feeling powerless and helpless, and they turn to violence as the only means to strike back.
In an ideal world, the boy would be taken into a public square and flogged 5 or 6 times. No lasting damage, but a nice amount of pain, and a nice amount of embarrassment. Instead, we have the kid who is now a hero to his friends, and a mom that's likely to be brought up on assault charges.
All the while, our politicians, lawyers, and legal system continue to fail over and over again.
Let's face it - if that lady thought she could get appropriate satisfaction from our legal system or the police, she would have gone that route. She obviously understood what we understand - the legal system simply can't deal with this and neither can the police.