Place for my reasoning for common things.
Citations edit
I certainly cannot argue that requests for citation can be overused [citation needed], but truly common knowledge is often not useful to include in an article in the first place: "People have faces." At the other end of the argument, maybe the common knowledge is not detailed or specific enough. "Whales are big animals." -> "Whales are large ocean mammals ranging from 10 to 1000 meters long." And once the phrase is more specific, citation is appropriate. Citation is an easy way to settle disputes about the correctness of a statement, by referring to a more authoritative source than a "random editor".
To specifically address the topic, pretend you are someone who was raised by wolves (who inexplicable taught you English and have access to the Internet). Reading this article, would you be at all confident that this is not someone's joke? Citations are evidence that what the writer perceives as common knowledge is in fact common knowledge.