The doka of the day pretty much sums up what OSensei thought of believers or non-believers.
What matters is that the guy's original post wanted to know the difference between the ki and the not so ki influenced dojos. If you concentrate on that mark perhaps this thread won't degenerate into another to ki or not to ki discussion.
Besides, the human mind needs this kind of assurances from time to time. Imagine if you were to walk down a painted line about 4 inches wide. It just enough for you to walk on if you put each foot infront of the other.
I bet that this would be an easy exercise for most of us.
Now imagine as it were you were to walk on that same width, a brick wall for example on a 3rd storey building. Would you have the same confidence as before?
But a ki sensei would probably tell you to feel your center and walk as if your center is being pulled by a string, thus effectively giving you the balance you need. Another practical sensei would say that nothing has changed so go ahead and do what you just did before. The choice for you to learn from which sensei depends on which type of person you are. Neither is wrong.