From what I can tell he's being unbiased in his presentation of historical models. Whether it's true what he says I don't know because I'm not familiar with all this.
So I'm not the person to seek an answer from. However, if you do want an answer in cosmological terms to explain why god isn't necessary you'll be thrilled to know that there was a book written for this very purpose.
Victor Stenger - God the failed hypothesis (how science shows that god does not exist)
I haven't read it because I'm not that interested in cosmology, but it's easy enough to find on the internets.
I wasn't really asking you about the validity of the cosmological explanations he gives but rather the final part when he comes to the conclusion for the existence of God.
1. Whatever exists has a reason for its existence, either in the necessity of its own nature or in an external ground.
2. Whatever begins to exist is not necessary in its existence.
3. If the universe has an external ground of its existence, then there exists a Personal Creator of the universe, who, sans the universe, is timeless, spaceless, beginningless, changeless, necessary, uncaused, and enormously powerful.
4. The universe began to exist.
From (2) and (4) it follows that
5. Therefore, the universe is not necessary in its existence.
From (1) and (5) it follows further that
6. Therefore, the universe has an external ground of its existence.
From (3) and (6) it we can conclude that
7. Therefore, there exists a Personal Creator of the universe, who, sans the universe, is timeless, spaceless, beginningless, changeless, necessary, uncaused, and enormously powerful.
I think his initial premises are all valid, and his final conclusion was exremely logical. What did you think?