Wow, Wikipedia developed over time a set of internal editing philosophies and users can express their agreement to a certain philosophy simply by adding a specific template in their user page.
So I could extract the following pie chart from the Wikipedians by Wikipedia editing philosophy page. (Update: as HaeB says in a commento “categories are not disjoint (…) a pie chart might not be the best visualization”. A bar chart might be better…)

The main ideological dichotomy is between Inclusionists and Deletionists. Inclusionists favor keeping and amending problematic articles over deleting them, Deletionists favor removing articles that are not encyclopedic. Currently there are 1123 self-declared Inclusionists and 261 Deletionists.
As it is typical of Wikipedia, fun enters the stage and a new philosophy emerges AWWDMBJAWGCAWAIFDSPBATDMTD, acronym for “Association of Wikipedians Who Dislike Making Broad Judgments About the Worthiness of a General Category of Article, and Who Are in Favor of the Deletion of Some Particularly Bad Articles, but That Doesn’t Mean They Are Deletionists”. Currently this the 3rd most frequest philosophy with 434 adherents, denoting how Wikipedians likes to have fun ;)
And in fact the 6th most frequent philosophy is WikiGnome (makes useful incremental edits without clamouring for attention, works behind the scenes of a wiki, tying up little loose ends and making things run more smoothly, fixing things like typos, poor grammar, and broken links) but there are also 265 WikiFairies (beautifies Wikipedia by organizing messy articles, improving style, or adding color and graphics).

Myself, I think I’m a Darwikinist or maybe not … ;)

Below the complete table and the same pie but in 3D.
Well, there’s a lot of Philosophy(ies) in Wikipedia! ;)