This is less relevant for the current discussion about the FireTV and this feature. It's for the more general discussion of being able to do whatever you want on a device you own.
Bad example; this "narrative" is true as often as it isn't.
Perhaps. Perhaps that should also mean there are consequences to their actions and they get disconnected from shared systems.
You can't force them to change their mind.
The real answer: users are captive. For the vendors, they're cattle. And like with any good big farm, it does not matter how much it sucks for the cattle - but it does matter the cattle is safe, because few bad cases can become known and risk your farm getting shut down.
Are you sure you responded to the right comment?
That's the should/should not part. The rest is my take on why companies remove those features anyway - they have no incentive to provide anything above bare minimum, especially not when they could be on the hook for "some fraction"'s mishaps.
I didn't raise the 'should/should not part' at all, you are the one who raised the point. I'm focused on actual facts and possibilities in this comment chain.
You don't have to allow all users everything, but you should allow those who want, to do as they please.
You can always hide the option behind some kind of mechanism. A mechanism a general user wouldn't use because they don't if the rest works as intended. Those who still do, should suffer the consequences, but this is not the manufacturers' problem. They have all kinds of safeguards to prevent liability because of those "special choices".