It's not an inside joke, it's a Freudian typo, a transitional form in the evolution of creationism into (new! improved!) intelligent design.
Full disclosure: I've never read "Of Pandas and People", and I don't know how many of the people arguing for ID here have read it. Needless to say, for several people to keep using the exact same obscure typographical error to mock those with whom they disagree is still Pavlovian behavior.
But I would like to thank you for the link. Here's an excerpt from that blog entry:
Of Pandas and People (1987, creationist version), p. 3-40:
“Evolutionists think the former is correct, creationists accept the latter view.”
Of Pandas and People (1987, “intelligent design” version), p. 3-41:
“Evolutionists think the former is correct, cdesign proponentsists accept the latter view.”
I went to the original source, the NCSE website, to see what other evidence they had there, and they had good stuff. Daisy-wheel printers were standard for word-processing work at the time, and the pictures they have of the drafts are monospaced impacted text (like a typewriter), so that's a plus for the NCSE's evidence.
The "word" in question, however, was not edited by a find-and-replace function; it was done by hand (as in probably moving the cursor to the "r" in creationists and either typing with typeover enabled or just using the Delete key afterwards, latter being the most probable).
What's even more likely is that the word-processor in question was not a PC (or other contemporary microcomputer - we used DEC Rainbows in my 1986 class) attached to a daisy-wheel printer. If I had to make an educated guess, it was a dedicated word-processor, basically a typewriter with a small LED display and enough memory to hold a decent number of text pages (the same amount of memory as you get in a cereal box toy these days).
All of this really means nothing, though, because it's never been disputed that ID and creationism overlap each other, just like Darwinism and Epicureanism overlap each other.
Therefore, it's not really all that controversial that the author of "Of Pandas and People" would borrow some ideas from a creationist text, just like it's not really all that controversial that cosmologists would borrow the idea that the universe is 16 billion years old from
the Torah (once they finally abandoned the erroneous idea of an eternal universe from a much later Greek text).