Wikipedia has an extremely left-leaning bias (not extreme, but certainly not balanced) to be precise. To say that it voices the average western opinion is moronic.
E.g. the article on communism has an extensive "history" section that mentions all real-world accomplishments of theory, but you will not find anything even remotely objectionable in there ... despite the fact that they were running extermination camps at the time.
To say that this is typical of pages on political theory is dishonest. The article on nazism, for example, does seem to find the need to mention what happened in the real world in the second paragraph. Something not found, at all, in the communism article. Well, to be fair, if in the edit history of the page, you will find that a reference to "mass killings under communist regimes" gets added, then removed again, then added again ...
... on page 37 of the printed page.
... page 37 ...
no bias there ...
There are other extreme leftist biases in wikipedia : you'd think all religions are duplicates of christianity with jesus replaced by someone else and a slightly different backstory. The reality, that all religions represent fundamentally different moral systems, and thus have radically different views on basically all sensitive topics, is nowhere to be found on wikipedia.
Take an example, the fact that slavery ("indentured servitude", and other assorted forms of forced labour) is present in all religions, and only condemned by christian religion (and even then only in the sense that christians should not have slaves, bearing in mind that large subcults like protestants found it necessary to literally skirt the edge, claiming for example that companies like the east india trading company technically did not count as christians and thus could own slaves, with protestant guards enforcing the system, a practice explicitly forbidden by the pope, who tried, and failed, to militarily enforce it) ... you will not learn this on wikipedia.
But all religions have all sorts of opinions on all sensitive topics, but reading wikipedia you'd think islam advocates equality between men and women. Obviously any muslim, and anyone with basic knowledge of religions, knows better (no religion has true equality between the sexes. Even Christianity's position of theoretical ("legal") equality with the man as the tie-breaker, not allowed to override a woman's wants but nevertheless the ultimate decision-maker, is extremely progressive for a religion, again even such a basic position, only mildly controversial, yet it is shunned like the plague from wikipedia). You would never know that equality between the sexes is such a difficult thing in practice, to the point that literally even communism badly failed at it by today's standards.
Topics like islam's basic doctrine of eternal war ... good luck finding those, despite the fact you'll find them on the second page of books muslim children receive in kindergarten ... "strange"
I find wikipedia to be biased to the point where revisionism accusations are justified in most historical articles. The encyclopedia Britannica is much less biased. And that means it's not for children, it for example speaks in extremely cold and detached language about the nazi's actions. It does not hide socialist massacres on the xxth page, and you will readily find them starting from the word "socialism", as it should be.
Likewise, Britannica is much more respectful of religions and ideologies. Speaking in equally cold language about principles like protecting the weak and the commandment for women to set themselves on fire if their man dies within a week after the funeral.
Wikipedia has serious troubles processing reality, and lets any sufficiently large mob enforce it's sensitivities on pretty much any article.