It's a joke and I apologize firsthand. So, could the school football team be named "The Green Bay Crackers?" [msn.com]
I think actions like this are a direct of result of poor education. So many times I've seen people think that because slavery was "so long ago" and people who doubt the holocaust even happened that it seems to me that no one is teaching thorough history so kids do stupid shit like this because all they know is that it will piss a bunch of people off.
In this age of social media, kids do things to gain "likes" without thinking about how it will impact their futures. Immaturity was at the height of this prank.