Humility is open to those who do not believe in God too, hence it does not mean accepting God, it can be a religious value, but it is not one at the core. Humility is being unpretentious and honest to yourself and those around you.
Did I say that I say that it wasn't? I was answering the question in the context of the topic which is "What is the nature of Christian Humility"
I believe in Christianity as I believe that the sun has risen: not only because I see it, but because by it I see everything else.