It's not that hard to get around this. I kept my TV offline and plugged in an Apple TV immediately.
I can't decide if it's better to check for such things before purchase, or just return it as defective if I end up getting a model that does this.
If it doesn't say on the box "requires constant internet to function" in big bold letters, it should.
That would be a ridiculous requirement, because people expect that TVs need electricity. But the producer can argue that people these days also expect TVs to need the internet, can't they?
You can fix that with a piece of tap or blu-tack.