Censorship

Kids are allowed to wear Christian shirts to school and have them appear in yearbooks; why cant kids wear atheist shirts to school? Censoring this kids "God is dead" shirt is kind of bias when it comes down to it. Now I dont necassarily agree with the message on his shirt but after all arent some of our oldest laws in America freedom of speech and freedom of religion? If schools are going to censor things like that they need to censor everything not just certain things.