" … Santa Claus again could be a very valuable lesson because the child will learn that there are some things you are told that are not true. Now isn't that a valuable lesson? Unfortunately it doesn't seem to have had the desired effect in some cases, because after children learn that there is no Santa Claus, mysteriously they go on believing that there is a God." (emphasis mine)
In other words, according to Professor Dawkins, believing in God is no different from believing in Santa Claus. Consequently, it is mysterious to him that some children (and adults, presumably) abandon belief in Santa Claus while clinging to belief in God.
I have to say that when I read the quotation above I was rather astounded that Professor Dawkins would say something like this. True, it's no surprise that as an atheist Dawkins would say this, but it is rather puzzling to me that someone who is obviously quite intelligent (a world-famous scientist) would imply such a simple-minded analogy . Yes, I suppose it could be argued that Santa Claus resembles God in that he is an object of faith for many, but one who cannot be directly observed. However, not all objects of faith are equally worthy of belief. We all place our faith in something, whether it is God, "science," "reason," or something (or someone) else. The question, though, is whether it is reasonable to place our faith in that object of belief. The fact of the matter is that it is not reasonable at all to believe in the existence of Santa Claus. First of all, Santa Claus has never been observed in reality--he has never been captured on film coming down a chimney, for example. His supposed home at the North Pole has never been discovered. Moreover, whatever evidence might be presented to support the existence of Santa Claus--like presents appearing overnight beneath the Christmas tree--can easily (and convincingly) be explained as actually being the result of the actions of verifiably existing beings, namely, parents.
On the other hand, whether we ultimately choose to believe in God or not, the notion that God exists is not completely unreasonable--it is at least possible. Yes, like Santa Claus, God cannot be observed directly. However, unlike Santa Claus, the evidence for His existence is considerably more extensive (and that is an understatement!) and far less easily dismissed. For example, the fact that the physical conditions that exist in the universe are exactly those needed for the emergence of life suggest that some Intelligence is behind it. The fact that nearly all human beings appear to have knowledge of some absolute Moral Law suggests that there is a Divine Lawgiver. The documentary evidence for the resurrection of Jesus (and the lack of a realistic alternative explanation for the empty tomb) strongly suggests that there is a God, for only an all-powerful God could raise a dead man to life. These are but a few pieces of evidence. Of course, many have offered arguments to refute this evidence. Nevertheless, the sheer amount of putative evidence for God's existence makes belief in God at least not totally irrational--unless one wants to argue that any belief in the supernatural is irrational. The problem with asserting the irrationality of belief in the supernatural is that it requires a philosophical commitment to materialism (the belief that only the material world exists, and, consequently, that nothing exists outside of the material world). Materialism may be (at some level) a plausible explanation of the world, but it cannot be absolutely proven to be true. Thus, like God, it is an object of faith.
Moreover, I'm not sure why Professor Dawkins finds it mysterious that people more readily give up belief in Santa Claus than belief in God. After all, rejecting belief in God has a lot more implications for how one views his or her existence than rejecting belief in Santa Claus!
Still, to be fair to Professor Dawkins, I have to say that in the case of some people, believing in God is rather like believing in Santa Claus. I have in mind those people who believe in a God who is benevolent but totally nonjudgmental, and who is obligated to give his devotees whatever they desire and/or to keep them from any misfortune. The God these people believe in would seem to be a celestial version of Santa Claus! However, a "celestial Santa Claus" is not the sort of God I or any other orthodox Christian believes in.
Finally, I have to wonder whether Professor Dawkins would really want children to be encouraged to be always skeptical. After all, learning to be skeptical could just as easily lead to disbelief in neo-Darwinian evolution (or atheism) as it could lead to a rejection of "supernaturalism"!
Image of Jonathan Meath as Santa Claus from wikipedia.org