It would also be awkward if an interviewee wanted to come back to my apartment for drinks. Interviewing and dating are two different social situations with different codes of etiquette.
Now, if he had been hired, worked hard for a couple of years and was promoted from within the interview story could be considered relevant advice. However it is too early for anyone including himself to glene any pro/cons out of it, and instead the blog post looks like a kamikaze mission to the top of the hill to let his buddies know where the enemies are hiding.
I have read several version of this comment elsewhere in the story, is there any basis for this attitude besides paranoia? Have you ever seen something like this be "dangerous" for a company in real life, or is it completely imaginary? You use the word "easily," so I'm just wondering if it's so common that I just don't get out enough.