To be fair to the editors, the inch measurement is just coming from Apple, that's how they refer to it. If the editors converted the model name into centimeters they'd be using a different name than Apple, and probably losing some search traffic as well. But I feel your pain: it's not even a great description, because the screen isn't 13 inches, it's 13.6 or something like that.
I can deal with the screen sizes, as they are used everywhere ( it's similar to e.g. 3.5mm jack I guess) and you know what's meant by that, but stating the thickness in inches got me.
