I view it more through the lens of serving the right content to the right audience. Markdown is great for agents (and some humans), it is not great for many humans. And it _certainly_ isn't acceptable to some humans that have the job title "designer" ;)

If you want to take the stance that those designers (and people who don't want to consume plain text web) are wrong, sure I guess. But I prefer to take the stance that people and agents should receive content in their desired format.