The rule is pretty simple: YC backed start-ups get to post job ads using a special mechanism, everybody else lines up for the who-is-hiring posts.
"On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity."
Don't find that UK's defence is hiring a wargames designer is curious?
If you feel that it is interesting then you're welcome to upvote the entry.
If you're suggesting it's simply impossible to discuss notable job descriptions on their own, that would be a bit sad. Alternatively, if it's that this isn't sufficiently notable, I guess that's arguable, but I found it interesting :|