Now this article seems to be coming from a standpoint that separation of the two concerns is somehow novel. A bit odd to say the least. I think this is where the o.p. was deriving sarcasm.
Perhaps the real story is the separation of concerns in the ruby module wrapper, instead of at the c library level? I don't know.
(Except no one was claiming that it was a novel idea, just that in the past, most Markdown processors just convert directly between Markdown and HTML, but now they are changing that. It's also funny that there seems to be some animosity in that post towards Ruby programmers for whatever reason. It's not like Markdown is an invention of Ruby, the reference implementation was written in Perl.)