While I do think that the group has a valid point {why should everyone be forced to use a semi-religious oath?}, I really don't see the big problem. Atheism is a belief system, just like Christianity, Islam, Buddhism, Paganism, Zoroastrianism and any other -ism you wanna throw in there. I'm sure that if there was a Buddhist President they would not force her *hint hint* to say "so help me God" on the end of her oath or to have any religious figure there. While the inauguration is viewed by millions in person, on the tele, and over the internet, it is mainly a ritual for the President (elect) to express his feelings for his/her country and newly elected position. If Obama wants to have a priest there as a part of this momentous and special day for him, why not let him? If someone else wanted Tony Robbins or some other motivational speaker, I'm sure that would be allowed. And, weird as it might be for some, if a person wanted the Dalai Lama there, I'm sure there wouldn't be a lot of objection.
Why, then, is the atheist group so obsessed with not allowing a freedom to Mr. Obama?
My thinking is that many people see others expressing their religion as a push for others to believe the same way. Sure, I might not like that my family is all Mormonism, all the time {yes, even more than the BYU channel}, but do I have the right to ask them to refrain from expressing their beliefs when I'm around? Absolutely not. According to the First Amendment:
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.
While that might only really apply to Congress and the legislative wing of the government, we also have EEOC and other laws allowing people to express their religion without fear of persecution as long as they also respect the beliefs of others. Going along with that, why can't the atheists in this group be okay with Obama's expression of his religion and be fine with the difference from theirs?
Why can't any group in the world be perfectly content in the fact that other people believe in different things and not force those same people to conform to their belief system?
If we could fix that problem, I think we might actually achieve world peace.