It's a salient point. Why do you think the Kinect is always on... added entertainment? It's to mine consumer data.
*sigh*
The reason the XBox ONE Kinect is a mandatory part of the system isn't part of an Orwellian scheme to watch you sleep and monitor you for malicious thoughts. There's a minor chance it could be used to "data mine", which really only means that it'll monitor your skin's pigmentation during certain ads, to see if you're "engaged" with the product. But there's a high chance that tech might not even work, and if that data would even be useful to advertisers. Frankly, there's nothing to say that you can't just point the damn thing at a wall & cover the microphone with tape.
It's a required part of the system, because that's the only way Microsoft can convince developers to use it. Remember the earliest model 360s? The ones that didn't contain hard drives? That decision ended up biting Microsoft in the ass at the tail end of this generation, because developers had to compromise their games. They couldn't rely on a hard drive being present in the system, which made making huge games like Halo 4 a complete nightmare.
They aren't going to fuck that up again with the ONE. There will be a Kinect in every box, and so it's impossible for an SKU without a Kinect to even exist - it's a mandatory part of the architecture. But it's absurd to think that the Kinect will need to see you in order for the console to function. New Kinect might be miles better than the past version, but I'd bet good money it'll be far from 100% foolproof. This is the same reasoning why we'll never see the "Only x amount of people are authorized to be in the room to watch this content" patents come to fruition, because they're comically easy to trick.