<Edit/Repost>
I had originally titled the question as "Ask HN: Bug or stupid HN policy?"
Previously, I had submitted http://news.ycombinator.com/item?id=1542329. However, the "discuss" link for that post didn't show me a comment-box and that prevented me from commenting on my own posting. I had incorrectly assumed the missing comment-box was either due to an HN bug or HN policy.
It turns out (thanks to RiderOfGiraffes) that the post (a New York Times article on "Israel Puts Off Crisis Over Conversion Law") had been killed (presumably because it was flagged as off-topic). That explains why the post had no comment-box.
If a post is killed, I wish there was an easier way for the poster to know about it :)