Some of this has to do with concerted and long-running campaigns of coordinated editing (against wikipedia rules) to push a one-sided political narrative. Most notably this happened and continues to be done by Israel-eliminationists[0]. Wikipedia eventually acknowledged the problem and banned a couple of the worst offenders[1] but that's a drop in the bucket as far as I'm concerned. I read it less and less these days and don't consult it at all for anything controversial ("controversial" meaning "topics that leftists have strong opinions about").

Sadly, a system like Wikipedia is hard to defend against persistent coordinated attacks by people who have lots of time.

0: https://aish.com/weaponizing-wikipedia-against-israel/ 1: https://www.jpost.com/business-and-innovation/article-833180