This essay contains the advice or opinions of one or more Wikipedia contributors. Essays are notWikipedia policies or guidelines. Some essays represent widespread norms; others only represent minority viewpoints.
The article must state the facts that result in the use of the category tag and these facts must be sourced.
Not even an exception for ones that aren't contentious. But consider this for a minute: Dan Goldstick is in several categories. With absolutely no references (as of October 2007) at all, his article claims (and categorizes based on those claims) that he is:
Of course, the categories should be removed even under a legitimate reading of policy, and some would say (or, they'd say if they disliked having articles about Canadian politicians for some reason) his article should be blanked too.
These policies are, I think, just as often used as a weapon for people to remove material they dislike for some other reason, as they are to genuinely improve the encyclopedia.
In early 1981 the upcoming Tom Petty and the Heartbreakers album was slated to be the next MCA release with the new list price of $9.98, following Steely Dan's Gaucho and the Xanadu soundtrack. This so-called "superstar pricing" was $1.00 more than the usual list price of $8.98. Petty voiced his objections to the price hike in the press and the issue became a popular cause among music fans. Non-delivery of the album or naming it Eight Ninety-Eight were considered but eventually MCA decided against the price increase.
Petty told Rolling Stone, "I seriously doubt that there is any negative intent there. And a lot of rock 'n' roll songs sound alike. Ask Chuck Berry. The Strokes took 'American Girl' [for their song 'Last Nite'], and I saw an interview with them where they actually admitted it. That made me laugh out loud. I was like, 'OK, good for you' ... If someone took my song note for note and stole it maliciously, then maybe [I'd sue]. But I don't believe in lawsuits much. I think there are enough frivolous lawsuits in this country without people fighting over pop songs."
On September 21, 2006, Tom Petty and the Heartbreakers received the keys to the City of Gainesville, Florida, where he and his bandmates either lived or grew up. When questioned about the key he received from Gainesville's Mayor, Petty quipped, "It's a lot nicer than the one we got in Chicago."
"This is an emergency crisis we’re in. The entertainment media is affecting everything on the planet in a very negative way. I’m only interested in rock ‘n’ roll. Rock ‘n’ roll is a music that represents truth. Your TV channel has taken the word “rock” and knocked the “roll” off the end. You made rock this umbrella term for everything. That’s wrong. Shakira isn’t rock. These country artists with fur coats aren’t rock - or country. I offered a video to VH1 of my band playing in the studio and they don’t want to air it because it had musicians playing in it. They want some babe walking on the beach or whatever. I got turned onto this music by watching the Beatles and the Rolling Stones actually on TV playing their guitars. It completely took me over. When you can’t see musicians playing any more, I’m not interested any more."  – To VH1
In preparing this, I have not checked to see if any of the material which did not have inline citations could be sourced to some of the existing sources (but, I don't think this has been done when this has actually happened to articles on less popular topics, so it's fairly realistic in that respect). What remains may have WP:WEIGHT problems, and should therefore also be removed. The infobox, Images, ELs, and See Also; have been removed to save space. Headers have been otherwise retained to show how much would be lost.
For a more striking example, here is what Port Vincent, South Australia (or, I'm sure, dozens to thousands of other articles) would look like if all unsourced material were removed: