When you watch Netflix videos in the Chrome browser, the service disables Chrome's developer console, a debugging and programming tool that gives you transparency and control over what your browser is doing. The Hacker News thread explains that this is sometimes done in order to stop an attack called "Self-XSS" that primarily arises on social media sites, where it can cause a browser to leak nominally private information to third parties. But in this case, the "Self-XSS" attack Netflix is worried about is very different: they want to prevent browser owners from consciously choosing to run scripts in the Netflix window that subvert Netflix's restrictions on video.
This is the natural outflow of the pretense that "streaming" exists as a thing that is distinct from "downloading" -- the idea that you can send a stream of bytes to someone else's computer without the computer being able to store those bytes. "Streaming" is at the heart of "rental" business models like Netflix's, and there's nothing wrong with the idea of rental per se. But the only way to attain "rental" with computers is to design computers so that their owners can't give them orders that the landlords disagree with. You have to change the computer and its software so that you can't see what it's doing and can't change what it's doing.
Your browser is a portal to your whole social life, your financial life and your work life, entrusted with the most potentially compromising secrets of your life. Anything that allows third parties to make it harder for you to figure out what the browser is doing, or to prevent it from doing something you don't want, should be a non-starter. As soon as a powerful entity like Netflix comes to depend on -- and insist on -- computers that owners can't control, that company is doing something wrong. Not because rentals are bad, but because taking away owner control from computers is bad.
This is why it's such a big deal that Netflix has convinced Microsoft, Apple, and Google to build user-controlling technology into their browsers, and why it's such a big deal that Microsoft, Apple, and Google have convinced the W3C to standardize this for all devices with HTML5 interfaces. Any time we allow the discussion to be sidetracked into "How can Netflix maximize its revenue by enforcing rental terms?" we're missing the real point, which is, "How can people be sure that their browsers aren't betraying them?"