You posted a random job ad to Hacker News and it got flagged. Part of what makes Hacker News Hacker News is that established people in the community can snipe off-topic posts from the site, and that happened to you.
There have been a few other job postings on YC, but they tend to be unusual -- either revealing that the hiring organization is awesome or clueless. Since posting a job can be fairly expensive, it's a good idea to be careful. I've written at least one job ad targeting the kinds of people who visit news.yc (not for a tech position, though), but posting it would be counterproductive.