I dunno, that kinda seems like throwing a bunch of straw-man arguments and unjustified claims like
>Anybody using a simple text editor is very fast at adding markup for headings, font variations, and so forth. The previous section proved that other markup languages clearly fail in many cases.
Markdown is not quick to add markup with a simple text editor? Really?
No, it has a single tool's support and no spec (though it's in progress last I saw, which is great). Almost everything else compared in that page is superior here, having specs (even if multiple competing specs, e.g. commonmark vs github) and multiple implementations.
Also there's a super comprehensive guide if you want to go all in on Emacs side of things. It's written in org itself http://doc.norang.ca/org-mode.org and exported to html http://doc.norang.ca/org-mode.html.