Quick point of etiquette - not only would I not downvote based on disagreement, it's actually IMPOSSIBLE to do so when the comment in question is in reply to one's own comment. It's a HN feature to avoid the downvote becoming a kneejerk response to back-and-forth discussions.

You use one reviewer's statement that that person prefers an ebook. There's no further explanation as to why (s)he prefers that format, and no data behind it - just a single comment.

I expect that the primary issue is, in fact, what you say - fairness over cost of production. That does not logically lead to your assertion that the two are "same thing delivered in different ways."