Where do you draw the line if they didn't? If everyone was allowed to submit whatever title they wanted, it would quickly degrade into Digg-quality submissions.

Where do you draw the line if they didn't? If everyone was allowed to submit whatever title they wanted, it would quickly degrade into Digg-quality submissions. In rare circumstances, it is necessary to change titles. A piece of content might not have any title at all, so needs one. It is better for the health of HN that mods act on the conservative side.