The author has inadvertantly stumbled upon a part of hacker culture with wide-ranging implications, that is almost never discussed—and that is that people expect that you publish code because you want it to be changed, and not simply read. This stems from a deeply-rooted tradition in programming of not reading a codebase until you have a problem with it that you must fix. People don't "read for pleasure" in the programming world; they don't even read to learn—have you ever had a school assignment that charged you with reading more than 1KSLOC? The only reason, as a programmer, I will ever "cd src/", is that I am on a mission to fix a problem. Therefore, publishing code but reserving the right to derivative works, looks a bit like gloating, or showing off—"look what I did! Look how smart I am! It's no benefit to you... but look!"

This makes perfect sense in the art world (and writing is a form of art), as you never really "derive" from a piece of art; instead, you first look at the mechanisms by which it communicated its message to add those techniques to your repitoire of skills, and then re-use those skills on your own works. That makes perfect sense in an artistic medium, where any single stroke or word or note may be chosen from an infinitude of options—but programming requires formal grammar—a finite set of ways of expressing each concept—and thus there is relatively little merit in studying the technique by which a single problem was solved.

On a separate note, for the first few paragraphs he seems to be completely unaware of the medium of fan-fiction—which is about as core to "the culture of online fiction" as you can find.