Are you saying they're constitutional because:
1. they have already stood constitutional challenges?
2. you're a constitutional lawyer arguing for these laws to remain on the books;
3. or you're completely biased for the fascism of religion/monopoly on belief?
Part of the first amendment is freedom of speech. Implied in this legal notion is the ability one has not to be forced into saying anything AKA no forced oaths of loyalty (that and the fifth amendment). Atheism is a system of beliefs and can be interpreted as a religion or even an areligion and still be protected under the first amendment's establishment clause.