There are multiple entire websites out there criticizing Wikipedia and what they have to say tends to revolve around the editing process, specifically the social/cultural aspects. Have you attempted to research this yourself?
e: another comment elsewhere on this post brought up another source: https://www.tracingwoodgrains.com/p/reliable-sources-how-wik... . I've read a bit of it and can generally endorse what's being said there. In particular, some specific usernames are cited and I recognize most of them, which in itself is telling. Other comments here suggested that Sanger's personal views are less than scientific, to say the least. I have not looked into this personally, but I don't think this in any way negates the argument about bias. (Nor is any political camp immune to pseudoscience.)
How do we rate biases, and what’s the rank of Wikipedia along the diverse methodologies to do so?
Also note that the issue is biases in there whole generality. Most data produced by the universe will just not attract interest of most human beings. Or at least, as finite beings, we have to pounder where we put our attention and can’t afford to study every single topic with the same level of scrutiny.
Are you familiar with what Larry Sanger himself had to say about the bias that has emerged in Wikipedia (https://unherd.com/newsroom/wikipedia-co-founder-i-no-longer...)?
e: another comment elsewhere on this post brought up another source: https://www.tracingwoodgrains.com/p/reliable-sources-how-wik... . I've read a bit of it and can generally endorse what's being said there. In particular, some specific usernames are cited and I recognize most of them, which in itself is telling. Other comments here suggested that Sanger's personal views are less than scientific, to say the least. I have not looked into this personally, but I don't think this in any way negates the argument about bias. (Nor is any political camp immune to pseudoscience.)