That linked page is so full of bullshit it's hard to skim through. There are some good points: various interest groups using Wikipedia as a platform to promote their worldview, sexist bias leading to important women being denied their page... but there's also a lot of unsourced or shaky assertions.

it is interesting to see here how easily administrator privileges are given to random users by other administrators, suggesting a widespread problem in the hierarchy

Source? The specific governance varies with every language community, but at least in the French-speaking Wikipedia is administered by a registered non-profit. I can't say i agree all the time with their positions, but their power is transparent and no power is given to random people.

There have been various examples in the past of administrators who used their privileges to prevent their articles from being edited (therefore presenting their biased opinion as fact), or even asking for payment to let an edit through.

Source? I've never heard of either though i don't consider it impossible, but you have to remember that all admins are all-powerful: a single admin can not control the site, so such allegations imply that the whole staff is on it?

Wikipedia is purposely kept difficult to edit

Source? Wikipedia has been constantly "improving" the participation UX. I personally prefered their old interface but i appreciate the new one is easier to use.

It is not rare for users going against the agenda set out by the administrators to simply be banned on frivolous grounds.

So the source for this is down now, but we can read it on the wayback machine. So it's an interview from this guy Kohs who denounces that some people writing on wikipedia have an agenda and we should be aware of that and check sources/history. Good advice so far. Oh wait this guy is behind that scandal and was actually paid to do commercial PR on Wikipedia and was banned for that... funny ;)

Since most Wikipedia editors are white, it follows that Wikipedia will promote white supremacist points.

This makes no sense. First, i'd be interested in ethnic/religious/cultural stats on Wikipedia. Second, these stats should be made by language community because every language has its own policies on Wikipedia. Third, in the history and geography of humanity, whiteness is not necessarily linked to white supremacy. White supremacy itself is a rather "recent" phenomenon that started with european colonization and the rise of capitalism. It's also not present in the entire "white" world: for example racial oppression in France is mostly a form of cultural supremacy, not white supremacy. Or as a french rapper put it, "here they love you when you're rich and eat pork".

Although Wikipedia purports to be a reliable and neutral source of knowledge, it has been mangled by several known cases of corruption, involving paid editors hired to whitewash their clients' reputation.

True. Wikipedia even has a dedicated page on that topic. Why not link to it?

Ultimately, Wikipedia is designed to promote imperialist interests; it naturally follows that Wikipedia will also promote white supremacist, anti-Semitic, fascist and sexist viewpoints in their articles. Not only are most edits made by accounts managed by/for corporations and government agencies, the whole website structure is made to keep this agenda in place and going strong.

Source? I certainly see bias on certain language communities, but arguing that Wikipedia as a whole promotes "white supremacist, anti-Semitic, fascist and sexist viewpoints" is a very far stretch. If anything, the french-speaking wikipedia does exactly the opposite although i disagree with the liberal "rough consensus" that most pages reach.

The article on the genocide that happened in the Congo Free State (...) claims that the term genocide is contested and currently, the article contradicts itself, first making it seem like the Congolese Genocide was caused mainly by disease, later saying it was caused by "harsh economic exploitation, rather than a policy of deliberate extermination".

The article doesn't appear to contradict itself. It points out that deaths can be mostly attributed to disease, while still pointing out countless colonial atrocities. It does not appear particularly bad or biased to me.

All in all, that article is full of FUD. Wikipedia has bias and strong debates, but this "prolewiki" article lacks both. In that sense, it's a lot worse than most wikipedia article that i come across. Too bad for something that's supposed to show how unreliable wikipedia is...

EDIT: Their page on Anarchism is also hilariously bad, as if it was written by interns working for The Party™.

Anarchism does not go beyond general phrases against exploitation, it does not understand what the causes of exploitation are, nor the class struggle as a creative force for the realization of socialism. The anarchist denial of political struggle contributes objectively to the subordination of the working class to bourgeois politics.

Wow. So much wrong in that sentence. Yes anarchism has some economic analysis: the entire cooperative movement was born from Proudhon's theories (he can be criticized on many other topics but that's not exactly the point). There are anarchist unions such as the CNT in Spain and the IWW in USA, both of which have been very involved in revolutionary activity and were the biggest unions of their time. The quoted sentence is an easy dismissal that's completely disconnected from reality of anarchism as a political struggle.

After 1917, anarchism in Russia became a counter-revolutionary tendency

LOL. More like Bolshevism in Russia became a counter-revolutionary tendency and slaughtered dozens of thousands of workers who were real revolutionaries.

Anarchism saw brief surges in popularity in Catalonia, the Free Territory in Ukraine and in the Korean Peninsula.

It's insulting to reduce decades of popular struggles to a dismissive sentence grouping together very different histories under a single umbrella. If anything, anarchism in Catalonia was the driving force of the socialist movement for a long time... many peasants learnt to read in anarchist circles, and the CNT was the biggest union with over 1 million members in Barcelona alone. Wikipedia also has short but good articles on the Ukraine Commune and the Korean Commune.

Examples of anarchist experiments

• Capitol Hill Autonomous Zone

Fun fun fun. If you'd like to name TAZ/ZADs, then let's name a few more: Standing Rock, Notre Dame des Landes, Hambach... We could also mention anarchist communes, or libertarian communist (anarchist, in my view) territories like the zapatistas caracoles in Chiapas, or the free communes from Catalonia/Korea/Ukraine we mentioned earlier.

SOOOOOOOO after examining two articles on your "source" i'm glad to say it's entirely bullshit and if you want practical/useful information you should stay away from that "prolewiki".