Well, I don't think that Chick really accepts that conclusion. But I don't see how "The day that changed Harry--forever" would have gone differently if Harry had not been told about Santa etc, but the children had taunted him over Jesus instead. (Obviously Harry is not a Christian by Chick's standards, but we know that he has been told about Jesus.) If we are to blame stories about Santa etc for his actions, then we stories about Jesus are just as dangerous.
Now that I write this out, perhaps Chick would agree. Stories about Jesus of the sort that you get in wishy-washy liberal churches (especially Roman Catholicism) are harmful, according to Chick. I came to my conclusion by assuming that Chick would never consider stories about Jesus to be harmful, but this was a mistake. So you are right.
I've long entertained a dubious regard for the practice of lying to children about the existence of Santa Claus. Parents might claim that it serves to make children's lives more magical and exciting, but as a general rule, children are adequately equipped to create fantasies of their own without their parents' intervention. The two reasons I suspect rest at the bottom line are adherence to tradition, and finding it cute to see one's children believing ridiculous things.
Personally, I considered this to be a rather indecent way to treat one's own children, and have sometimes wondered whether a large proportion of conspiracy theorists owe their origins to the realization that practically all the adults in the country really are conspiring to deceive children for no tangible benefit. However, since I began frequenting this site, I've been exposed to the alternate viewpoint that this realization may be good for developing rationalists, because it provides children with the experience of discovering that they hold beliefs which are wrong and absurd, and that they must reject them.
So, how did the Santa deception affect you personally? How do you think your life might have been different without it? If your parents didn't do it to you, what are your impressions on the experience of not being lied to when most other children are?
Also, I promise to upvote anyone who links to an easy to register for community of conspiracy theorists where they would not be averse to being asked the same question.