Source: The Washington Post
http://www.washingtonpost.com/wp-dyn/content/article/2010/07/04/AR2010070404268_pf.html
The trouble with most major holidays in the United States, if you're an atheist, is that it's difficult to ignore the "holy day" etymology, what with Christmas (obvious), Easter (obvious) and Thanksgiving (whom do you think most people are giving thanks to?). But not the Fourth of July. The Fourth is a little deity-free celebration stationed in the middle of summer for believers and nonbelievers alike.
"Especially now, when atheists are v ilified for not being patriotic enough," Maggie Ardiente says, balancing her paper plate of cookout food, "this is a really important holiday."