I imagine the thinking is that if the TV is not connected to any WiFi, it might try to connect to something public or non-password protected neighbornet so it’s better to connect it to something non-functional rather than unconnected. Of course, the TV could just lie about what it’s doing anyway...

I wish there were more dumb TVs on the market. What kind of dystopian market is it where you can't even trust an appliance you own to not spy on you.

I think it's because the phrase, "None of your business" has fallen out of common use.

I would hear that all the time when I was a kid. I don't think I've heard it in public in decades. Or maybe I was just a nosy kid.