If someone is offended because someone else said "Merry CHristmas" Happy Hannukah. . .or whatever holiday it might be, if they wish you have a good one, then really you(This is a generic you, not to any specific poster) need to just get over yourself, stop being perpetually offended, and say 'thank you'.
So to all of the perpetually offended class. . ."MERRY CHRISTMAS!"