You're correct.
But that's not what we're talking about. We're talking about a web browser that can understand its posting a Comment, not a form (or a random collection of key-value pairs). The primitives that make the web work are quite different from the high-level concepts that make an application work.
My browser understands how to display links and forms and text and graphics. It does not understand how to display a comment or a user account or the number of votes a comment has, let alone know when I'm allowed to vote up or down, understand the relationship between a user account and a comment, understand a comment being owned by my user account or another, etc, etc.
What exactly is the end goal? That a HATEOAS-style REST API can be created, you can go to some entry point with your browser, and with no one writing any UI code it just understands how to render the Hacker News site? It will magically understand that the main page contains a list of articles, those articles have comments, links to an original source, etc?
This is my understanding of the goal of HATEOAS. If that's not the goal, I don't understand what it gets besides being a way to build a tiny part of documentation necessary to consume an API.
A website is a RESTful service which a generic client can interact with despite not having any custom code. Does it do so by magically understanding what an <a> or <img> tags are or by magically decoding PNG bytestreams? No, the service uses standard formats that the browser knows and which encode these semantics, allowing it to process them despite its original developers quite possibly not even knowing that service existed.