[stomachmonkey]

There is no mystery here.

It's not the hardware.

The device, like every other one, has a base horizontal.

Apple decided using tagged data vs in device processing was a better option for performance and battery life.

Shooting with the lens in the upper left corner is base horizontal.

If you rotate from there and don't post process before posting it may or may not show up the way you want depending on where you post it.

But that's the fault of the destination not honoring the embedded data that tells it how to display it the way you want.