I felt like the author did realize that, and the "written by the devil" comment was a direct reference to autoconf (which certainly qualifies as a devil). Who knows, though.
zetalyrae also correctly pointed out that much of the text is "handwritten but transcluded". Most of the code snippets that appeared in autoconf was originally written by hand and stored in reusable modules, including 100+ tests in autoconf. So overall the volume of code is still huge.
I guess it at least demonstrated the power of modularity. Almost nobody can understand it, but it still works...
