Well I'm not too familiar with the U.S. constitution, but there was a very large issue in France about banning religious symbols such as the Muslim hijab and headscarve, as well as other icons such as 'large' crosses and David's Star, etc. The law was only valid for public schools and buildings so it's quite similar to the protests against christmas, in particular, displaying the famous nativity scene.
After some research, I actually discovered that the French constitution didn't protect the citizens right to publically display their religion, instead, it appears France was built around creating a secular country with no religious face, and as such, their laws were created to support this. As a consequence, when someone claims that banning religious symbols in public places is abusing their 'rights', they're actually incorrect, they never had that right in the first place. This only relates to France though, and perhaps Petrat... err, Ben, could verify it's correct.
The point I'm trying to make is that you may be a little amazed to find what the first amendment actually does and does not protect. I wouldn't be the least be surprised if a lot of people had a few misconceptions about what rights they really have.
Edit: And here you go, America is nothing like France:
Quote: "Amendment I - Freedom of Religion, Press, Expression. Ratified 12/15/1791. Note
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances."
However, that can easily be interpreted to mean that you have the right to choose your own religion, but it says nothing about being able to publically express that religion.
"Computers are useless, they can only give you christmasy answers."