Because the comment is just a copy/paste of the content at the URL at the top of the comment; which doesn’t add anything to the discussion, because it’s not discussion at all. It’s just a wall of text, it’s not clear to me why you’re posting it as a comment (vs linking to it), and simply regurgitating copy/pasted external information isn’t helpful or interesting.

Next time, write a sentence or two of context about what you’re going to link to — who wrote it and when, why it’s interesting, and how/why it’s relevant to the topic at hand.

There’s almost never a need to copy/paste wholesale external content into an HN comment. Especially true when said content is literally linkable, and actually linked, from your comment!