I will only ban if he says it twice because if you where a black / white person getting offended by what he is saying you would want it to stop as soon as possible because no-one wants to be offended just because hes different but before that I would Warn him and !mute / !gag him.

i have got to grips with the regular scenarios that I could be in as mod

but you sometimes do not know what to do on some situations