"The current crop of evangelizing atheists – most notably Richard Dawkins (The God Delusion), Daniel Dennett (Breaking the Spell: Religion as a Natural Phenomenon), and Sam Harris (Letter to a Christian Nation) – want to convince agnostics that tolerating religion is wrong. The time has come, they argue, to drive the delusion out. ..."
Gruntled uses religious imagery to describe such people as Dawkins, Harris, and Dennett (the latter I am not familiar with), and this may not be well-received by the trio, but in terms of the belief system and the proselyting in which they engage, I think the choice of words is apt.
Belief in a negative (i.e. "there is no God") is logically unprovable, thus atheists must have faith, especially if they are going to engage in a crusade against those whose faith leads them on a different path.
Read Gruntled's full posting -- it's short, but packs more into its few paragraphs than most people could say in a considerably larger essay.