The notion of what a blog post is I think hinges on a very early 2000s notion of a blog, from a very particular web subculture (that loved CMSs, and RSS feeds, and posting rather than making). The idea referenced in the linked gemlog that "a blog needs a title because the W3C mandates a title for all documents" is kind of silly - I mean, I can leave it out, and it won't validate, but it'll still render, y'know? But at a more philosophical level, why does the W3C have any particular say in what a blog post is? That's community-determined.
In fact URLs could be easily detected by the browser / text reader.
Even my terminal detects URL and allows to click them.