As in any venue, the people who understand the rules and have the most friends.
What do you do when some quackery gets repeatedly put into a medical article?
What do you do when Nazis try to say the Holocaust didn't happen all over wikipedia?
What do you do when spammers try to add their website to a bunch of articles?
What do you do when some middle schooler tries to add the word "penis" to every article they can?
What do you do about decade long edit wars (Israel/Palestine as one example) where the partisans on both sides will never stop trying to get their version of the article?
Further, do you not see the irony in claiming that wikipedia is run by "scary 'leftists' who lie all the time" and then trying to use wikipedia's description of itself as some sort of holy weapon?
If you really want to understand how wikipedia actually works under the covers, instead of ranting and raving without foundation, read https://wikipediocracy.com
Check out the forums.
Every bad thing ever done on wikipedia is in there, with cogent comments from both long time critics and from people who currently have advanced permissions on wikipedia.