Not the OP but I'll back him up, and I'll edit this comment when I come across them. They're pretty common. If the domain of knowledge is niche and the page is absolutely huge, that's a good sign to start looking for editoralizations and slants.

A lot of wiki pages about smaller companies only list the good things (fundraising, tech, etc.) and omit any controversies. The deliberate omissions due to bias are even more insidious than weasel words or other forms of poor journalism.

Fwiw I truly believe in Wikipedia and donate every year, but calling it "perfect" would be extremely dangerous (and false!)

I've seen this regularly on fringe articles that are clearly being manipulated. I don't have direct links right now, but things I have seen in the past:

* A sketchy online university that was clearly manipulating their Wikipedia page with lots of positive information about themselves to suppress info about their active lawsuits and controversies

* On medical topics: non scientific, baseless claims about the efficacy of various herbal treatments, vitamin supplements, or other snake oil treatments.

* On various fringe politicians. Someone clearly rewrites the article or adds additional things to the article with claims about what the politician has done or not done or wants to do, but these claims are arguably not fact based.

Now these things usually don't last for a long time. They do get rolled back or removed. But it doesn't have to be on there long for it to be utilized. For example, someone just needs to modify the Wikipedia page long enough to get through their active lawsuits, or the snake oil salesman just needs their info up on Wikipedia for long enough to use it to increase their perceived authenticity to trick some seniors. There is such a constant stream of bad actors trying to put this stuff out there that you'll see it eventually, and it doesn't even have to be up there for long for it to be harmful.

Many countries in Eastern Europe have radically different interpretations of history. The nationalists from each country will try to establish their own ethnicity for persons of interest. They will try to add editorial comments or hyperpartisan sources to all kinds of historical articles. There are edit wars about what language to use for what city in what era. I would guess that this is the case for many other regions of the world.

I came across a similar thing when I first read the Wikipedia page on 5G was it was in development. I read it after learning an early phones 5G power consumption was through the roof, and I was trying to figure out what benefits 5G had. I was accepting everything I read at face value, until I came across the section waxing lyrical about 30GHz. I knew 30GHz was stopped by glass, or a human hand, and so was more or less useless in a mobile phone.

So I re-read the entire page, this time looking for signs it was written by marketing rather as a factual document. Of course it was exactly that. Only the engineers deep in the bowels of the organisations developing 5G knew how it would perform at that stage, and evidently they weren't contributing to Wikipedia. Until the man on the street had experience with 5G, the marketing people were going to use the Wikipedia page on it as an advertising platform.

So I'm in agreement with the OP. From what what I can see a Wikipedia page that only has a few contributors it is no better than any other page about the same subject on the internet. The breath and depth of a Wikipedia page on a subject arises because of the wisdom of the crowds contributing to it. If there is no crowd, it's possible there is no wisdom.

Fortunately Wikipedia does have one other advantage over a random Internet page - you can tell when the have been lots of contributions. There is an audit trail of changes, and you can get a feel for the contentious points by reading the Talk page. That contrasts to getting the same information from an LLM, where you have no idea if you are being bullshitted.

As you might predict from all that, the Wikipedia page on 5G is very good now.

This is not exactly propaganda in the typical sense, but it clearly is the case that people successfully edit Wikipedia to further objectives. As an example, the Wikipedia page for Meta-analysis (which isn't even that obscure of a topic) currently contains content that seems to plausibly be trying to promote Suhail Doi's methods, and it seems that it has been like this for a number of years. It cites 5 papers from him, more than anyone else, of which the largest has 297 citations. It has a subsection devoted to his method of meta-analysis, despite it being a rather obscure and rarely used method. There have been additional subsections added over time, which also focus on somewhat obscure areas, but frankly these additions are sketchy in similar ways.

In general, it is not uncommon to come across slantedness issues. Is it completely 100% clear that Doi has come on and maliciously added his papers? Not quite, but good propaganda wouldn't be either, and would actually be far less suspicious-looking.

https://en.wikipedia.org/wiki/Meta-analysis

It’s not a niche topic, but anything to do with Iran tends to censor the bad things going on there.

Look up the page on ICE, it's straight up propaganda.

Many historical atrocities with death counts is a common one I'll run into.

You'll see "xy atrocity had caused the deaths of this many people*", where the additional note will say something like "The numbers reported in this study have been challenged by many scholars on the subject and has been accused of invalid methods".

It's super common with history around Communist countries, because for a lot of folks in the west, the black book of communism is taken as fact when it's far from it, and you have groups like the Victims of Communism memorial foundation that have huge coffers for pushing the black book line.

It says on there that the mRNA vaccine doesn’t kill you.

This is kind of an unreasonable request. The OP is making claim of a general trend not obscure and subtle bias on any single article. Informally the claim feels true from my experience with Wikipedia and it makes sense that a small number of editors would have a wider bias. Just think central limit theorem here.