The author argues this is a negotiation and that this is something reasonable and well thinking humans do with eachother; maybe they do in some magical HN dreamed up places, but most of the world is not like that; there is often no negotiation, not between plumber and client, not between car mechanic and client and not between dev and product/client.
But we don't know how most of the world is. It might be that the author of the comment works in a particularly bad place, of which there are many of course.