No, Protestant is the first step on the road to atheist. Protestantism is inherently dualistic, pitting spirit against flesh - faith alone is worthy, "reason is the whore of the Devil". The natural response to this dualistic world view is to reject it as erroneous, which it is. But this rejection itself goes overboard into Enlightenment philosophy - reason alone is worthy, faith is "the opiate of the masses."
Sorry, but atheism is simply the mirror image of the Protestantism which has infected the country from its founding.
You have an excellent grasp of American Christianity. Somehow the Puritans took the beauty that is true Christianity and turned it into something cold and ugly.
I've never had a Catholic (or Jew, for that matter) suggest I should be burned at the stake for my beliefs.