Have you read some of the articles on math subjects? It’s like they’re written for mathematicians by mathematicians.
Even some mathematics concepts I have a decent grasp on … the corresponding wikipedia entry reads like an alien language.
https://simple.wikipedia.org/ is a good alternative sometimes and I’m glad it exists, but that’s almost the opposite problem.
It does seem like they make an effort, their style guide starts out with “Probably the hardest part of writing a Wikipedia article on a mathematical topic, and generally any Wikipedia article, is addressing a reader’s level of knowledge.” https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Mathematics