The "Don't roll your own crypto" mantra is overly ambiguous and enforces the culture of elitism in information security. I hope that something displaces this regurgitated "advice" with something more helpful. I know Moxie's article is a few years old but it is a step in the right direction regardless.
--EDIT--
I don't think I was perfectly clear in my original comment. I attempted to expand on my position in a follow-up comment: https://news.ycombinator.com/edit?id=9376131