Student Suspended for posting "I wish Osama Bin Laden killed my Maths Teacher"

 Strange how Facebook can effect lives of School Children. But here, a 13 Year old girl gets suspended from her school for posting on Facebook that she wished Osama Bin Laden killed her Maths Teacher.
 Kimberly Dell'isola, the Girl's mother agrees that the comment was offensive, but says ,"She's mortified that she said that, but she's a 13-year-old kid,". She said her daughter was suspended for five days after saying she wished Osama bin Laden killed her math teacher.
  "You are denying her an education based on something she did at home. That's my business, not your business," Dell'isola said. The mother holds that the issue is a parenting one, and not school related. She said she expressed that sentiment to Principal Tom Sica. "He just said what she said was really awful. I started laughing and said I agree with you there, but how did it come to you deciding to throw her out of school," Dell'isola said. She said that while her daughter's suspension is over, she has not returned to class out of fear of facing the teacher she made the comment about.
Source: wmur.com
  Who's fault is it? Is it a problem of Parenting? Or an issue of Facebook as a whole? Facebook adds these statements in its Privacy Policy -
  • No information from children under age 13. If you are under age 13, please do not attempt to register for Facebook or provide any personal information about yourself to us. If we learn that we have collected personal information from a child under age 13, we will delete that information as quickly as possible. If you believe that we might have any information from a child under age 13, please contact us through this help page.
  • Parental participation. We strongly recommend that minors 13 years of age or older ask their parents for permission before sending any information about themselves to anyone over the Internet and we encourage parents to teach their children about safe internet use practices. Materials to help parents talk to their children about safe internet use can be found on this help page.
But isn 13 a bit too early for Facebooking? Considering all sorts of Social impacts it might have on the kid? And how strictly are the above rules followed? A survey reported that Over 7.5 million Facebook Users are Under 13. I strongly disagree with this Age limit, I was not even allowed to use a Computer at that age! Thoughts please!