Why do most Atheist seem to be lemmings?

When asked to give the origin of the Universe they tend to chant "Big Bang", as though this is their mantra and had been instilled in them as a part of their indoctrination. And that answer doesn't even make sense since it doesn't address where all of the material for their Big Bang came from. So it doesn't speak to the origin of the Universe but rather to something they feel came about after the origin. Are most Atheists simply mindless creatures only capable of regurgitating pat phrases to explain their beliefs, which so happens to be the same argument they use against theists? Are they the pot calling the kettle black?