Well, maybe problem.
In spite of the Constitution, religion is endemic in politics. Social psychologists know that no politician could possibly be elected to national office unless he or she were outwardly religious or pretended to be. Religion has always been in bed with governments, officially or unofficially. If it weren't for Constantine thinking that Christianity could help him consolidate his empire, we'd all be Zoroastrians today, and feeling patriotic about it. And Zoroastrian bishop-equivalents would still bless battleships and solemnly proclaim that the gods were on the side of whatever government they served.
The Freedom from Religionists are right, of course, in promoting science and reason over superstition and mind control. But when they announce their atheism they lose all influence. Nobody trusts a self-proclaimed atheist, not even other atheists. A recent study showed that the the trust level among Americans for atheists is identical to that for rapists. If you want to promote reason and science, demonstrate for independent universities (and note that some of the finest universities in the world started as religious organizations). Demonstrate for the values of secular humanism, while honoring the choice of people who substitute superstition or twisted scriptures for a superego.