http://www.guardian.co.uk/artanddesign/jonathanjonesblog/2008/sep/18/wikiped...
My answer (currently in the mod queue):
"The trouble is Wikipedia's aim to Neutral Point of View. It achieves this with great imperfection, but it is what we're aiming for. The trouble is that editors quickly gain an allergic reaction to any subjective phrasing at all.
"Particularly problematic are popular culture articles about living people. These attract (a) fans, who make them into hagiographies (b) obnoxious obsessives who confuse an encyclopedia with a platform for investigative reporting. Rubbish articles ensue.
"A reasonably reliable way around this is to quote the opinions of prominent critics (preferably noteworthy ones in themselves), noteworthy books on art/music, etc. This is of course more work and not easily remedied with a quick Google. Better hit that bookshelf after all!"
- d.