OK I see but we still are lacking an explanation. The display will play images in 1920x1080. I'm sure media player could play a 1080i/1080p mpeg file just fine on the display.
I'm guessing the only reason they say 1080p isn't supported is that the display's native resolution is "1200p". Therefore if you try to run a component 1080p input into the display it might not scale it or accept it properly. Just a guess.