Well, it's not Wikipedia's fault if people producing intuitive content are not contributing to it. It's not like editors go out of their way to remove nice explanations.
There are many anecdotal reports of tyrannical Wikipedia editors doing exactly this. They claim dominion over a subset of Wikipedia articles and then manicure them exactly to their own personal tastes. I'm sure the situation you describe happens often in various corners of the website.
I nearly based my Master's dissertation on a topic I discovered on a wikipedia math page when I was looking for something to cover. Turns out that subsection was maintained by the 'inventor' of topic and essentially served as a vanity page. The topic itself had no recognition in the community and if I had forged ahead on it, I would have failed my dissertation pretty hard.
Oh, I got rid of it years ago. Thanks though. Eventually a big-name mathematician (who some years later won a Fields medal) waded into the discussion and sided with me. I used my real name in that discussion so I won't give more detail than that :)
Well, I've personally contributed to small parts, and never encountered the problem. I don't doubt there are jerks on Wikipedia, but I would also bet that neither the author of this nice github repo or the praised youtuber mentioned in the comments even tried to commit anything into it.
Not that they should for some reason, but too often editing wikipedia is presented/thought of as something reserved to a happy few with deep social consequences, when it's in fact the simplest thing in the world.
The problem is more due to a general culture that prefer rigour over clarity. Mathematics by definition is made of layers upon layers of intuitive conclusions. Then why do universities prescribe books with long dry derivations over clear explanations? Rigour is important to ensure correctness - and that should never be compromised. But that isn't the reason why humans learn mathematics. People learn it because it extends their imagination. Clarity and intuition are important for that and those who can't see it becomes disillusioned.
Rigour is better left to computers these days. They are better at following rules. We can have better proofs with software like metamath. Surprisingly, you can even gain deep insights by writing automated proofs (compared to manual proofs). Ideally, practitioners should consider simple and clear explanations as their primary goal and equations and proofs as necessary supplements. Think of this as literate programming for mathematics.
I think it is wikipedia's fault, but that it's not far from how it should be. Wikipedia is a secondary source, designed have be a reference taken from primary sources, rather than be a primary source teaching information. It's a weird blurry distinction, but seems to work well. It'd be great to have a pedagogy section that either explicitly linked out to pedagogical primary sources, or a section explicitly designed to teach.
