Imo this kind stuff probably because these “dev” having safe space on those discord servers rather than using something properly setup site/forum.
Heck you can make your own documentation using github/gitlab built in wiki or if you want something fancier, setup a site using JAMstack/static site generator, pick suitable theme then use gh page to host it.
I even more hate this stuff when the files is gated inside discord server, dude out of all possible file hosting services why the heck you would use discord?
As someone who mostly lurking back in reddit, lemmy sort of forces me to engage (give back) in community. While at first I felt weird, it grow on me to contribute for discussion and hopefully I can start my own post in a community lol.