I assume you mean you're confused on being downvoted. I did not think a downvote on your comment was warranted, so I gave it a corrective upvote.

In general, it's not worth worrying about one downvote; that one person did not like your comment enough to downvote it is a rather weak signal. There are a lot of users on HN. Other users (such as me) are also likely to give you a corrective upvote. It's when you get multiple downvotes that the signal matters.