This is slightly misleading advice. The ideal place for the display has the top of the display at roughly eye level, or for a very large display maybe slightly above, which puts most of the display below eye level. Humans actually have great ability to look slightly downward for long periods of time while doing stuff with their hands, even while keeping their head held up straight, and indeed our eyes can more comfortably focus on close objects in the lower part of our field of view than straight ahead. What you don't want to do is slouch or bend your neck too much.
A laptop display attached to the keyboard usually isn't an ideal placement, but it's generally not too bad.