It's that he is really bad at conveying the moral of his stories which is generally "God loves you." The evidence he provides for this is generally that the protagonist of his stories generally triumph over adversity. However, the adversity in question is generally so horrible that you wonder if God doesn't actually want these people dead and just keeps screwing up. "Your entire family was murdered when you were a child, your friends were killed by a circus freak whose satanist father had a grudge against your family, a deranged conspiracy of art critics tried to kill your wife and son, and your serial killer brother inserted a live mammal into a orifice of your body into which live mammals should not be inserted. (Note: These are all things that actually happen to protagonists in Dean Koontz novels). But your not dead. Clearly, God is looking out for you."
In my opinion, this is the true moral of every Dean Koontz story: When you have a friend in God, who needs enemies?