What's baffling about it? If someone were to only read the title and not the article and came to the comments section, a summary about the title would be desired. What you're probably baffled about is why do people only read the title and not the article.
I’m not sure... HN is supposed to be real time discussions of articles. summarizing the article not only is not discussion (read it is regurgitation / bastardization) but any argument / discussion had based on the summary will be inaccurate as they are going off of the words of another, who more than likely integrated logical fallacies that did not exist before the comment.
FWIW this happens on reddit too as so many posts have clickbait titles, people are trained to go directly to the comments to find out the non clickbait version.
I often check the comments first to see if there is one as clear and concise as CJ's. Then I don't need to skim a lengthy article for the information I'm interested in - such as the answer to the question in the headline in this case.
Some people rather quickly see the reason than read about the leaves blowing on one crispy fall evening as a dog howled in the distance and the city lights twinkled beneath the moon.
