Are you sure? That article talks about how unbiased Wikipedia is:

>Our study finds that crowd-based knowledge production does not result in articles with more biased than articles produced by experts when the crowd-based articles are substantially revised.

Larry Sanger, the co-founder of Wikipedia, also gives a number of examples of Wikipedia's bias in this article:

https://larrysanger.org/2020/05/wikipedia-is-badly-biased/

> when the crowd-based articles are substantially revised.

You literally just had to keep reading to find the cases where they do show bias

That's just saying that highly-trafficked, highly-edited articles are going to be less biased than articles with fewer contributors or sources. That... just makes sense, to me; the more visible or relevant an article, the more people (and potentially experts) will weigh in, and the more crowd consensus will drive out the more blatant biases.

It also mentions there a bias in both directions, depending on the topic. Plus, it only considers US viewpoints/political alignments, and not Canadian, British, Australian, or other countries.