Sam, that site is an online community that rates music (funnily enough), so if you look long enough, you can find someone bagging anything. On one review of Nirvana's brilliant unplugged album, it got slagged mecilessly by some pub band rocker who sounded jealous as because he was not afforded the same level of success and celebrity.
Check out the yearly albums lists, double click on the cover to read reviews of the albums. That 'worst artists' list is compiled by ratings provided by users of the site. So sign up..and save 50 cent
regards,
20 cent