Well of course this phenomenon is not exclusive to Darwin's "disciples."
By "disciple" in the Darwinian case I mean a person who sees in Darwin's theory more than it claims to hold. The theory is not an origin-of-life theory; it is a theory of speciation and evolutionary change in species. It starts with organisms that are already alive. There's nothing in the theory that explains what life "is" or how it came about. And yet the disciple is attracted by the fact that Darwin's theory is relentlessly "naturalistic," materialistic, and effectively claims that the biological sphere is, in the words of Jacques Monod, the result of pure, blind, random chance. Therefore, the origin of life must be likewise.
The disciple is happy, because with this strategy he has succeeded in finding, as Richard Dawkins put it, that he, too, can be an intellectually satisfied atheist.... [The entire point of the exercise is to kick God out of the picture.]
What this has to do with the natural world or even with science is another question entirely.
Then we've got people pointlessly "filling in the blanks" with stuff that isn't really there but that they would agree with if it was.
Then we've got other people who are rationally and logically "filling in the blanks" with stuff that isn't really there, but that they would disagree with if it was.
And thank you for the examples of "filling in the blanks" from the atheist corner.