Firstly, it's clearly a bit tongue in cheek: "The evil doctor cackled as the thunder struck his lightning rod, giving life and sentience to his unholy creation, spliced together from iphone, ipad and mac ui." And the vulgarity is right in line with other satirical, single purpose sites like http://www.whatthefuckshouldimakefordinner.com/ and others I can't think of right now.
Secondly, he's got a "legitimate" complaint. You don't have to agree with his point, but I think a lot of people who are passionate about design (and about design in the context of their Mac) really, really do experience visceral rage at the way Apple flouts the HIG. A site like this is really just capturing that zeitgeist and reflecting how heated people actually feel about the topic.
Anyhow, I really am a big proponent for civility in discourse (that's why I'm always reading HN), but everything has its place.