When the media and others refer to a "militant atheist," the object of that slander is usually an atheist who had the nerve to openly question religious authority or vocally express his or her views about the existence of God. Conventional wisdom quickly tells us that such conduct is shameful or, at the very least, distasteful, and therefore the brazen nonbeliever is labeled "militant."
MORE: http://www.psychologytoday.com/blog/our-humanity-naturally/201102/the-myth-militant-atheism
See also...
Do atheists have a place in America?
http://gargoyle.flagler.edu/2012/03/do-atheists-have-a-place-in-america/