As moderators we can only guess why people flag things, but there are other reasons why people may have flagged that comment, the foremost being that it broke the guidelines due to its inflammatory style.
On Hacker News we want to be able to discuss difficult topics involving arguments people may find counter to their assumptions, but you need to express things in a way that's persuasive rather than combative.
If a comment of yours or any other you see is unfairly flagged, you can email us and we'll take a look. We'll explain how we see it and if we agree its unfair we'll restore it and consider action against those who flagged it.
We always discourage complaining about flagging or downvoting in comments as you can never know exactly what has been done by other users or why they did it, and it’s usually a generic tangent from the discussion.