Who made this decision at Best Buy? Do we know the identity of the person who banned "Merry Christmas" in this company? Someobdy who does such a drastic thing should have to publicly explain why. If he's not ashamed of his decision, then why shouldn't he be willing to step forward and take credit for it, and explain his reasoning?
Just say no to Best Buy
I am a Christian, but it's as a traditionalist that I insist on saying "Merry Christmas" to everyone. People used to say it to one another all the time, and the world is less friendly, less hopeful, less unified when we all sullenly refuse to say it.
That said, I can understand why some stores have such a policy where I live. I live in the Washington DC area, which is trending toward being minority Christian. Some of the people from other cultural backgrounds get pretty fiesty here. You say "Merry Christmas" to the wrong person here and you can find yourself on the receiving end of hysterical shouting from someone from India or Arabia or even New York who chooses to feel offended. I don't mind saying a few brisk things to people who don't accept my heritage, but the store managers mind quite a bit.