Do you think the exercise is worthwhile to get Atheists out of the closet and say "I am not afraid of you... theists"?
Worthwhile? Probably not. I'm not overly familiar with the Rational Response Squad, but this whole exercise seems more to do with advertising themselves and jabbing at theists than actually extending a helping hand to atheists that are afraid to admit they are atheists. In fact, I'm willing to bet that very few of those taking part in the Blasphemy Challenge would fit that "closet" atheist description. The whole thing comes off as preaching to the choir at the enemy's front gates.