That link is a perfect example of how subjective all of this stuff is. I don't have any issues reading that page, though I understand how you might!

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.