That is a good point.
Higher res. screen and retina display are at some point the same. Apple coined the term retina display to be any display which has a high enough pixel ratio, that the eye cannot see,or distinguish the pixels. Retina display does not mean a certain resolution, dpi, or anything, it is a completely wage term, as it's only restriction is a lower pixel density.
I would assume that when people say retina display, they think of the iPhone display, which does look crisp and want a similar display on the iPad. In the end retina display means a higher resolution display and this is probably what most people ask for when saying retina display. But since higher resolution and retina display go in the same direction, higher resolution, I.e. smaller pixels, is the message to take away: higher res. screen, regardless of how it is named.