In a very real sense, every person who denies God is living of borrowed capital. He enjoys living as if the world is filled with morality, meaning, order and beauty, yet he denies the God whose existence makes such things possible. When you start with theism - "in the beginning God"- these destinations make complete sense. When you start with materialism though - "in the beginning, the particles" - that route takes you over a cliff of absurdity and despair.
There is no neutral ground when it comes to the tolerance question. Everybody has a point of view she thinks is right, and everybody passes judgment at some point or another. The Christian gets pigeonholed as the judgmental one, but everyone else is judging, too, even people who consider themselves relativists.