There is a difference between 'uncalled for' behavior and someone slipping up and doing something offensive. I think that most people have made a comment that has come out wrong, but I dont think that we all should be labeled a bunch of racists.
Yahoo sports writers need to back off because I doubt that the chef guy was trying to start a race riot, in fact I think that by bringing it up Yahoo is doing more harm than good.
The expression of 'like water off a duck's back' mean that whatever the situation, the person just lets it go and doesn't stress about it. Some people let things upset them easily while others are more laid back, this is where the expression comes into play.