Actual point: Dear gods that 4am crack is awful to read, and I'd actually prefer github angry fruit salad in spite of mostly hating the latter.
So, yeah, there are virtues to simplification, but it can still be overdone - and while the article we're commenting on was great to me, it probably overdid it slightly - and the link you provide is an unintentional reductio ad absurdum of the approach.
(long comment written because I expected to disagree with you until I clicked and went aaaaaaaaaaaaaaaaaa)
Here's a blog post I've always found interesting about Markdown, from Joe Armstrong: http://joearms.github.io/2016/03/21/Why-Markdown-Sucks.html
Plain text documents don't solve the problem he's talking about, but they at least mitigate it somewhat -- WYSIWYG is preferable to a changing pseudo-standard mangling an author's intent, in my opinion.
A stronger example of the problem is, I think, some of the text from 4AM documenting their ongoing reverse-engineering efforts, for example: https://ia600509.us.archive.org/6/items/Muppetville4amCrack/...
The 40col text might be "retro", but it also makes lines wrap so soon that my eyes get tired reading it. (And yet—unlike e.g. an RFC file—I can't just plop it into a Markdown parser or what-have-you to get reflowable lines of HTML out, because 1. it's not really in any particular format, and 2. the alternating "prose text", "formatted console interaction", and "formatted ASM listing with long prose comments beside them" sections aren't demarcated or delimited in any particular way.)
When your text becomes sufficiently "simple", it can actually become an accessibility problem.