I think this is partially discounting the people that do genuinely try their best to keep Wikipedia factual. There are certainly many people that contribute to Wikipedia and do an excellent job trying to maintain factually correct articles all across the site. AFAIK, they are not paid for this. In particular, math related pages tend to be the most pure pages since there is little room for opinion in such a topic.

The problem is that even just 1 user abusing their "control" over a Wikipedia page will throw the entire site's credibility into question. People like that, unfortunately, are often ones that seek out places where they can have "power." Controlling information, or globally accessible pages that document events in history, no matter how small, is incredibly alluring for this kind of person.

It is an issue inherent to the Open-Source style approach of Wikipedia. Anyone can make an edit, but any edit can also be reverted. For topics where opinion is introduced, this often leads to Edit Wars, fighting in Talks, and the eventual locking of the page so no further edits can be made.