Now all the down-voted ones are supposedly by: https://news.ycombinator.com/user?id=_hhkg
@dang, care to explain what transpired here? Are you protecting someone's account from down-votes?
We try not to delete posts that got replies, because doing so would be unfair to the other commenters in the thread. At the same time, we don't want anyone to get in trouble from anything they posted to HN, so we help people who ask for help. We just try to do it with more precise tools than wholesale deletion.
This is in the FAQ: https://news.ycombinator.com/newsfaq.html.