This statement means nothing. It is an expression of belief, not a proof, or even statement, of fact. So Dawkins' work *denies* the existence of God. So what? There are also works that deny the existence of the Holocaust, or the moon landing, or Elvis' death. Each would claim to be "thoroughly researched and expertly executed", and each would be essentially nothing more than nonsense supporting a nonsense proposition which is itself based on nothing but assertion.
Shhhhh, please don’t point out the paradox of Dawkin’s ascribing to a religion of disbelief instead of a religion of belief. You know how hardheaded those religious fanatics can be. :o)