Self-dealing is a bad look no matter how you try to spin it. Being fussy about what is and isn't "encyclopedic" (arguably a self-defining idea anyway though) is fine, until it benefits you to rule a certain way, then people are going to speculate.
Also, nobody knows how much money Jimmy Wales took home from selling Fandom to TPG/IMC.
The problem was in the early days when people were still mocking the idea of a crowd-sourced encyclopedia, journalists would snark about how (for example) the article on Captain Kirk was longer than some historical figure. So you can see how fictional content was seen as "embarrassing"
It really was. Outside the nerdosphere, articles about fictional people or places in TV, movies or games were widely mocked and seen as "unprofessional" -- people were saying if Wikipedia needed to be more like Britannica if it was going to be taken seriously.
So when Stack Overflow operates Stack Overflow, for programming questions, and Super User, for usage questions, and directs a computer usage question to Super User, that's corruption?
It'd be suspect, if SO was a nonprofit, and SU was a budding commercial enterprise owned in part by Mr. Overflow personally, and Mr. Overflow had used his influence over SO rules to farm content for SU so that he could sell SU to PE and get rich.
Also, nobody knows how much money Jimmy Wales took home from selling Fandom to TPG/IMC.