The Changing Face of America asks "Should We Boycott Anti-Christmas Retailers???"
When I worked in retail, most of my customers were Jewish, plenty more were Christian, and a few were of other, less-known faiths. I got into the habit of withing people "Happy Holidays" so that they would know that I, a non-believer, wished them the best, during their holiday seasons.
There's no call for boycotting a business which does not wish to commit itself to a single message, especially if its own internal makeup is as diverse as, say, the giant retail chains are. They're not "anti-Christmas". They're trying to (a) run a business, and (b) deliver a friendly message without making assumptions about your own religious direction. Remember the warning about assuming things? Cut them some slack.
As to the angle that these stores are undermining the message behind the holy days... um. Look in the mirror. Are you practicing (a) forgiveness, (b) charity, (c) love? Lead by example. Drop holier-than-thou righteous indignation and learn to let them go their way. It seems to me, those who spend the day wallowing in their own greed never would have been much good at the faith thing, anyway. Let them have their sad, full houses and empty lives.
When somebody says to you, "Happy Holidays," just smile warmly, and say, "Thank you, and a very Merry Christmas to you."