Something can be technically correct, yet unreliable. How? Simply by reporting with a bias. The easiest example would be to look at a left (or right) leaning but accurate news organization like Vox or WSJ - they’re absolutely great at many topics, but read only one of the two and you’d have a slightly distorted view of everything. Being unbiased is incredibly hard even for newspapers, let alone a volunteer run org.

For a more specific example of wiki’s biases, think of the average Reddit bias - like their insistence of “if you can’t prove it it doesn’t exist”. A lot of people in the world would be very sad if they learnt that their god supposedly vanished.