The info is there and has always been there: in traditional, non-SEO optimized forums. But they have been flushed off the search results pages by irrelevant SEO optimized GitHub copycats and mediocre fluff text recipes.
When I test your hypothesis by searching for "2019 honda cbr1000rr wiring diagram" [1] the first results are images of the wiring diagrams and then links to the exact non-SEO optimized forums you're talking about with a post that contains a PDF file available to download for the exact motorcycle I'm interested in.
Its not the exact term I used over the weekend in my original post, but this is a basic enough one. Since it's more basic, it actually has a good result or two first. Then falls into spam upon spam. My original search over the weekend has only spam.
https://www.google.com/search?q=2002+chevy+s10+brake+wiring+...