Those are typographic eccentricities, to be pedant :)

And they're not even that uncommon on the Internet and amongst tech people. (See the Jargon file[1], for example.)

But I get your point: pedantry is often needless, and sometimes even lacks proper justification (see taejo's comment). But it's difficult to stop seeing errors when you see them, so I would forgive the parent for being that Hacker News guy.

[1] http://www.catb.org/jargon/html/writing-style.html