Technical documentation sometimes does contain humor, it's not that uncommon for developers to include jokes and easter eggs. Furthermore, this is listed under category "Poul-Hennings random outbursts", described as "You may or may not want to know what Poul-Henning thinks.". So while technically included in it, it's not really a documentation of anything. It's basically a blog post. And just like I don't find anything wrong about a blog about cosmetics or fashion assuming that the reader is a woman, I don't find anything wrong in a blog post about technology assuming that the reader is a man.