In other words, evolutionary theory, as a philosophy, is defined by what it denies. In this context, the absence of a cause is understood as a cause. We don't really need to grapple with the large idea of what might be understood as a 'first cause' or 'the ground of being', because, whatever it is that is behind it, it is not God. What is behind it, is the God that is not. The denial of the sufficient cause of being, is now the cause of being.
That puts me in a quandary, because although I want to agree with part of what you are saying here, and I think it's important, I first have to say that, at least according to my vague understanding of the neo-Darwinian theory of evolution by genetic inheritance, random genetic mutation, and natural selection, the scientific theory (a) is true (although it may not tell the whole story), and (b) does not in any way depend upon any hypothesis of a theological character, such as the non-existence of some specified kind of 'God'. It seems to me like an extremely well-supported and extremely important piece of genuine science. I'm almost 100% with Dawkins et al.
But the larger questions of why anything is the way it is are now met by the universal solvent of adaptive necessity. 'It is, because it survived. And it survived, because it is'. This is the Universal Principle which now replaces Ratio, Logos, The First Cause, Prime Mover, Moral Law, and any number of other superannuated religious and philosophical concepts which presumably are now confined to the last remnants of pristine wilderness prior to the woodchippers moving in. And furthermore, this principle is sufficiently elastic and non-specific to surmount any empirical obstacle that might appear to threaten it. That is one of the beautiful things about Darwinian theory: given that we lack the one real means of testing any of its hypotheses - namely, some other life-bearing planet - then whatever happens can easily be accommodated by a nip here, a tuck there. Easy, really.
That's the bit I agree with. I'm quite sure there is a kind of atheistic, scientistic pseudo-religion, in which the absence of a God is worshipped, and an evolutionary dogma is applied as a universal solvent to all problems. If the solution isn't intellectually very substantial, why then, the problem was no good in the first place, so there's no need to worry. All praise to the absent God, and let no infidel dog dare question His Divine Absence!
So, you are absolutely right; but so is evolutionary theory, as I see it. It's not perfect, but it's a good scientific theory, which deserves defending, or else the whole of science falls, and with science, the whole of reason - not because science is the whole of reason (it isn't), but because it is part of reason (although as a social institution
science, like religion, can be quite irrational - just as with 'God', we need to be careful as to what we are talking about when we talk about 'science').