I had a similar objection to the book (posted somewhere above). When he started discussing religious memes, I thought that he had gotten off track and out of the domain of science.
And if he had intended the book as a textbook for the layman, it could have benefitted from illustrations. That and the entire work could have been improved if a technical editor had been involved.
Another serious criticism is that although the book is in its 30th edition, it could have been brought up to date. Instead, he chose to write responses to his critics at the back of the book. A bit "cheesy" if you ask me. I think that he would have been better off just leaving the original book stand.
Too, the book is a bit dreadful to read from cover-to-cover, unless the layman reader is ambitious and has tenacity.
As far as the technical aspects and the credibility of same, I believe that Elroch can address those matters far better than I.
One thing that is certain, in my opinion, is that the masses are not going to throw out their holy handbooks in favor of this book. This is a given, especially considering that the book was first published in 1976.
btw...I bought my first slide rule in 1957. I bought my first four-function calculator around 1970. Nowadays, I have several computers, note pads and smart phones. Evolution at its finest!! 
Nitpicking on grammar and spelling is the sign of someone who feels he is losing an argument. I'm waiting for the inevitable "he calls himself a Christian and he said damn and wtf". When that comes I'll sleep soundly.
Here is the exact quote from the book, extended as much as copywright will allow:
“The chimpanzee and the human share about 99.5 per cent of their evolutionary history, yet most human thinkers regard the chimp as a malformed, irrelevant oddity while seeing themselves as stepping-stones to the Almighty. To an evolutionist this cannot be so. There exists no objective basis on which to elevate one species above another. Chimp and human, lizard and fungus, we have all evolved over some three billion years by a process known as natural selection”
Excerpt From: Dawkins, Richard. “The Selfish Gene: 30th Anniversary edition.” Oxford University Press, 2006. iBooks.
Quotes with sources does not violate copy write law.
I think what you are saying is the utilization of science to attack religion is tedious and that the theory of evolution stands perfectly well on its own.
I would agree. If the bulk of the text is as you have quoted I would burn the book before finishing it.
From your quotes Dawkins appears to have fallen into the same trap as theists in using the absence of evidence of one discipline to support a completely separate and independent discipline. As I said in another thread. Not comparing apples to oranges but trying to turn apples into oranges.
Pointless. Science stands on Science. Theology on theology. The merits of either should be judged accordingly.