i have no problem with respecting an atheist not using a bible. Like you said it means nothing to them anyways. Also I know atheist that are very moral and good people.
i am not a practicing Christian but I am a Christian. I do know our country was founded on Christian platforms and that is good and I hope we always stay a Christian nation.
I'm not shocked to see a president swearing on a bible.
At this point it's both an historical and symbolic act as it it a religious one.
I'm sure some atheists would have no problem swearing on a bible if they get elected president.
Same way many atheists still celebrate Christmas just because it's tradition.
The most important is that the president actually respect his/her oath of office, not the book used to swear on.
Too many swear on a bible to protect the constitution and then proceed to destroy it ...