From: "Lukasz Bolikowski" L.Bolikowski@icm.edu.pl (...)
This feels to me essentially the same issue as with the category tree: while some might prefer a strict IS-A relationship for categorization, in practice we have to accept that all that category >> membership means is some kind of hopefully human- understandable relationship.
(...)
A bug or two is in the sub-category tool (+) that is on cat pages -- as compared to catscan, which was written into those cat pages with enhancements. I think that's what the author means by "snafu" on catscan. Catscan can make a tree out of [[:category:neurology]] that includes more information.