I haven't watched the linked video, but the word "mistake" in no way applies to this situation. This was an entire week devoted to thinking up ways of being cruel to another human being.
The fact that human beings are capable of spending "an entire week devoted to thinking up ways of being cruel to another human being" when the other human being has been nothing but honest and welcoming is why I believe that we are an inherently evil species that doesn't deserve its place on this planet.
[1]http://www.youtube.com/watch?v=FPOezLL398U&feature=share