First, your point is irrelevant. Whatever the medium, this discussion is about cryptography. There is not a real case of hypocrisy here. Cryptography is certainly related to security, but as far as I can tell, that is not the thrust of this discussion.
Second, while the technology can be abused, as you point out, that is a far cry from this particular author abusing it and using it as a security attack. The author's PDF is fine.
I am not agreeing or disagreeing with you, btw.
In other words, I can see that this comment was downvoted because it did not meaningfully add to the discussion. I usually see downvotes on posts that include offtopic personal axe grinding. I may receive the same, myself, for this post, but I just wanted to help you avoid it in the future.