The paper cited is a much-referenced (in the PL world) classic. I can imagine finding the accompanying code would be an occasional if not frequent need to anyone who found the paper useful or interesting or even controversial.
I can think of no sane reason to close a useful question with a correct and useful answer. The only thing I can imagine is that since the mod didn't find the question interesting, they couldn't imagine that others might.
In the time it took you to post this, I saw your flag on the question and reopened it. :)
That said, closing a question isn't always a bad thing. I am honestly on the fence on this one, cause on one hand it has been answered well, but on the other -- it is a very specific request. The odds of someone else having the same problem are relatively low, which makes the question a good candidate for "too localized".
Still, ultimately I think it can't hurt to leave it open in case someone else does read the same paper (I've no idea how popular it is) and goes looking for the sample code.
