That's not a tile. Also, the first time I saw that text, I knew I could click it. I can't explain how they did it, but somehow being able to click it was just consistent with how everything else works. That's just me though, supposedly this guy tested with 12 people... and yet he conveniently omits the results for this task... oh no wait! "many users in our testing didn't click this command" How much is "many" out of 12?
First time I saw it was with a touchscreen device and I didn't find out that it was touchable until I had googled how to add more users to WinRT device.
Therefore YMMV
EDIT:
Negative karma for pointing out an opposite experience with a device?
Our opposite experiences just goes to show that UI qualities are subjective, and until someone releases scientific studies (none of this "many users" crap) that go against Microsoft's own user testing, I don't see why they should ditch their Metro experiment.
Really? Where is this problem? I know the tiles on my phone can all be tapped, without any exception (WP7).