I've upbooped this perspective but I disagree. Markdown trivially compiles to HTML and is justifiably loved (aside from the proud markdown haters, old and jaded and scarred by it not working for their weird usecase that one time), and you haven't suggested an alternative which addresses the problems they had with the mess caused by wysiwyg output. But maybe you have a better solution? Beyond the entitled expectation that it's someone elses job to fix it.

Also #6 of their manifesto is about interoperability. Markdown is a great choice for this if you are consistent in your approach. No lock in, human and readible.