In Orange County, California, there is a stretch of the 55 freeway where you can regularly see a billboard sign that has been paid for by a group of self-identified atheists. As you can see by the embedded image of Thomas Jefferson, these atheists just don't express their non-belief in any god, they are openly hostile toward religion; Christianity in particular. How do I know this? For one thing, Thomas Jefferson never said the words that these atheists attributed to him.
Watch this short video of Fr. Robert Barron on the new atheists (h/t The American Catholic). I especially like how he describes atheism as a drug that makes its adherents the very thing which they accuse people of religious faith of being: delusional.