Papers from academia present new results in a specialist area. It's not surprising that they will be less readable and contain more jargon than a manpage. The latter is intended to show how to use something for the general computer user, not how it manages to do it. Furthermore manpages have the chance to undergo many revisions, papers generally do not.
Being "not surprised" seem to be the new meme on HN. Anyway, let me disagree: when you know how to write words in a sentence, you do it well under any circumstances. (I forgot its name but there is a story of this British poet whose one-sentence instruction sticker on how to handle the toilet flush was such a precise and cristalline piece of prose)
So no, if academic papers are so poorly written now compared to manpages or academic papers centuries ago, it is because academic people are worse writers.
