Please know I am saying this online instead of to your face so as to avoid the massive argument that I just do not have the energy for. But saying "Happy Holidays" is NOT harming Christianity. It is acknowledging the other religious holidays during this time period as well as the fact that not everyone is Christian and/or celebrates Christmas (shocker, I know...). Please stop being such a bigoted idiot when it comes to anything trying to protect other religions' rights or sensibilities - everyone has a right to worship the religion/deity they wish, in fact that very right is mentioned in our Constitution (you know, the one you say made the US a Christian nation?). So hush!
Sincerely, your sister who is tired of keeping quiet around you