That is utter nonsense. Man has the right to life, liberty and the pursuit of happiness whether he was created by a god or not. I am an atheist and you would be hard pressed to find anyone more conservative. I believe in a strong, objective moral code and I can tell you why without saying because god says so. Conservative principle have their root in a belief in limited government, individual rights, capitalism and personal responsibility. No belief in gods is needed for those.
These basic rights could not be unalienable if they come from government or any man. Our founding document rightly states that it is because these rights, among others, come from God that they are unalienable.