> many that were written to promote various biased points of view, inadvertently uncritically repeat claims from slanted sources, or mischaracterize claims made in good sources.

Yep.

Including, if not especially, the ones actively worked on by the most active contributors.

The process for vetting sources (both in terms of suitability for a particular article, and general "reliable sources" status) is also seriously problematic. Especially when it comes to any topic which fundamentally relates to the reliability of journalism and the media in general.