That's fine. So many of the one sentence summaries (including the one for this article) read to me as being very dismissive, or as if the author hopes that their comment will encapsulate so much that you can glean the information or "learn the lesson" of the parent article through the summary, and now don't need to bother reading the post. If that wasn't your intent, then awesome, points to you. It is definitely how they almost always read in my mind, though.

I know the HN community is growing and the spread of topics pushed to the front page is expanding, but the original point of letting a user type in a headline and then letting the community vote up interesting ones should in theory at least alleviate the need for a summary.

I compared the summaries to "first post" because they often feel like someone is posting them simply to post. On HN you obviously couldn't "post for the sake of posting" with an actual First Post, but typing up a sentence summarizing the first or last paragraph of the post is probably close to the bottom of an innocuous "post just because you can" contribution.