Why is it il leagal to be Christian?

So here I am, trying to raise my family, teach my children morals, right and wrong, and all the other things that parents are supposed to do. Now, as a concerned Dad, with four kids in school I tend to follow things pretty close, and keep up with what they are learning. For years now I have been rather un-happy with some of the choices that I have seen the school districts making. Some of these started back when I was in school, and some are more recent.
It happened back when I was in school, that Christmas became a taboo in school. you didn't have Christmas break, it was Winter break. You couldn't do any class project involving Christmas, but yet we learned all about Kwanzaa, and Hanuka and other spiritual celebrations around the world. We stopped saying the Pledge of Allegiance due to the phrase "one nation, under God". Then I noticed that kids were being suspended for things that I thought were protected in this country. I had a group of friends in school about my freshman year, that actually were suspended from school because they refused to stop their prayer group in the lunchroom during lunch break.
Now, as I drive around town, I notice that churches are being required to remove the cross from the roof top, or front lawn. People are wanting our money to be completely redone, because it say "in God we trust".. It is becoming more and more difficult to be Christian in this Country. I am all for equality. I have no problem standing side by side in a line with people while I pray to my God, and the guy next to me prays to Allah, and the other to Buddah, and so on.. However, I will not stand by and watch as it becomes against the law to pray to my God. But I have to keep my mouth shut when the other guy prays to Allah. We have taken equality about thirty steps too far, and pushed it the wrong direction. It needs to stop. Historic Courthouses having to paint over murals that have been up for hundreds of years, because they depict the ten commandments, which are the basis for all civilized nations in the world. Not the part about God sending them down, but what they say.. Our US judicial system is based on them. As are every other legal system in the world. Remove Christ from our Country, you remove our Country from Freedom. The very freedom that we found this country for. The freedom of religion, choice, speech, practice, look, arms, earnings, and every other GOD given freedom.
But hey, lets not offend anybody else by being free, that would totally suck wouldn't it. I wouldn't be able to sleep at night..