I'll come back to one of my big points from my post above that you chose not to acknowledge:
If the War on Christmas is being conducted by private companies, what exactly do you want done about it? It's not in any way illegal, nor should it be, to use secular language in advertising. In fact, one could argue that these companies are not making "a conscious effort to reduce the influence Christianity has in America" but simply acknowledging the fact that it already has a reduced significance in the general population and catering to the secular majority. If you acknowledge even that 43% of Americans are church-going (which I still claim is artificially inflated) you basically have to admit that there is no "moral majority" in the way that the GOP refers to it. That's not to say that Americans are immoral or bad, but their lives are not necessarily guided by Christian values or ideals the way they were decades or centuries ago. At best there is a large moral minority. Now, you can argue that this is a bad thing. But trying to blame it on companies for not explicitly mentioning a holiday that, frankly, is fairly insignificant in the Christian calendar is just ridiculous. Frankly, the secularization of the country is already obvious from the fact that Christmas is a major holiday and Easter, which is FAR more important in terms of actual impact in the Christian faith, is an afterthought. Why don't you go after corporations that don't make a big deal out of Easter advertising? Christ's death on the cross is the central event that gives meaning to the Christian faith. His birth is far less important. If you disagree just check again how much space each event actually gets in the Gospels.
And just as a matter of interest, who, exactly, in your view, is it that is orchestrating this conscious effort to reduce the influence of Christianity in America? If you only point out its vestiges in the advertising of private, unaffiliated corporations, you have a serious burden of proof to indicate that this is any kind of organized, concerted effort.
And even if there is such an effort, why is that bad? Our country has always adhered to principles of religious freedom; they are explicitly protected in the Bill of Rights. If we're honestly going to say that an Arab or a Seikh are equal to a Christian in this country, is it really fair to want one of those 3 people's religion to have an influence in the government and not the others'? What if I practice voodoo or wicka and want MY religion to have an influence? Why can't we just look to have our country, in both the public and private sectors, embrace a strong moral center rather than a strong Christian center? Which would you rather have, crusader kings using Christianity to justify and gain support for campaigns slaughtering thousands of women and children in the Holy Land or Gandhi using secular peaceful protests to improve the lives of the lower classes in India? Honestly? Simply following the doctrines that one group of people attribute to a certain religion is far less meaningful to a secular government than general principles of morality that permeate nearly all major and minor religions.