Yeah a quick skim of the ends of the sentences on the page indicates that most if not all of the verbs are in the informal/non-polite form - and you wouldn't use the formal/polite form in the middle of the sentence anyway, so it's probably all in the informal/non-polite form.
And if you think about it, Wikipedia isn't a person, it seems kind of silly for a webpage to be polite (even though it is obviously written by a person). It's not like I've ever heard anybody say this or anything, but it kind of makes sense to me. Although I'm sure you could find many examples of pages that use the polite form, but I would imagine that they are written from the perspective of a human writer directly communicating with or speaking to a human user, as opposed to the knowledge-purveying nature of Wikipedia and other references.