Yes, "even" atheists. No kidding. Even Deists, like Jefferson! 


But it's been a battle from day one against conservatives who would deny free speech  except that they agree with, i.e, Christian free speech.


This is precisely WHY the founders set it up as a secular government. The Inquisition was still happening in their day, and I'm sure they were also fully aware of how the various Protestants were having intra-cult battles and suppressing each other, etc., in the colonies. Based on Jefferson's dialog with the Baptists of his day, many of them seemed quite upset and confused by the fact that the plan was not to let that continue with the blessing of the U.S. government.


Having freedom OF religion requires freedom FROM religion, too. Having one without the other is meaningless. It's probably the reason religion is still relatively vibrant here vs. many other advanced countries - government is not involved and does not endorse any religion, including xtianity.