They do lead to additional explanation—usually lots of it. For example, if you follow the link I just mentioned (here it is again: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...), is it really not obvious what the point is? The point is that we try to optimize HN for curiosity and that this has interesting consequences. You do have to scroll back through the search results to find the good explanations, but that's not so hard.

One thing I intend to do eventually is compile those past explanations into a set of commentaries that could be linked to in the future. For now, the genres through which I explain this stuff are (a) HN comments and (b) emails, and I can't link to emails, so you get past HN comments.