I don't think they are downvoting as a disagreement in this case. The answer seems self serving and less about fostering discussion about the information presented so much as self-aggrandizing.

It read, to me, like "I don't see why medieval monks cared about death since I don't." Then there was the dollop of "I am atheist/agnostic," which again didn't seem to be usefully on topic.

That isn't to say you shouldn't discuss these things, it is an interesting conversation to have... But look at where this comment was placed; on a summary of the article.

The whole thing just felt like something that deserved a place on Reddit's "IamVerySmart" subreddit rather than on Hackernews.