Most TFTs have pixels in accurate square matrix.
Remember that each "color pixel" is actually 3 individual RGB. Examine with a loupe.
So that was just an unsubstantiated assertion - or guess. Which means that each colour stripe must be three times as (?)high as it is wide as it is (?)wide - or more than that to allow for the spacing between. Or else a hexagonal "tile" in a tessellated pattern, like the original shadow-mask TVs which for engineering reasons switched over to the "Trinitron" pattern of vertical stripes which is what I presume these LCDs use. It would seem you are lucky it is so close to a "square" pixel.