Where are you getting the 90 angle stuff from? MS stand kicks it at a 22 degree offset. Which is why they made the camera able to adjust to that 22 degree offset.
Not a single picture of the device in kickstand mode shows it at 90 degrees. That’s simply FUD.
FUD? Read what I wrote three times and concentrate. Portrait mode is where the short side is the base. All pictures have shown the kickstand out with the long side of the Surface as the base. There is no practical way of standing the Surface on the short side, with the kickstand out, that would achieve anything other than a 90 degree angle of the screen to the table top. Darn uncomfortable viewing. Why people cast out the FUD statement before concentrating on what is written, is simply their own use of FUD!