And you would be wrong. I owned a rMBP 15" 2013 model from October 2013 to January 2014.
They look fine, when stationary. Once they start moving is when they start flicking. It's very apparent with thin text, 1 pixel lines etc. Even 2 pixel lines, when they start moving they switch from being thick 2 pixel lines to thin 1 pixel lines. It's very distracting.
Try opening an application that hasn't been optimised for retina yet that uses small text and welcome to flash city once you grab the window and move it around the screen. The scaler pixel doubles the width and height of single pixels. So 1 pixel becomes represented by 4 pixels. Then it attempts to downscale that final image (4K) to a 2.8K display. Those 4 pixels then have to fit in the space of 2-3 pixels. This is where the flicking occurs when you move the text around the screen. If the text isn't moving, it's fine. But if you're using a web browser for example and scroll up and down or use another app that isn't yet Retina ready it becomes insanely apparent.
But guys, I don't wanna like debate this with you. I can see it, I have eyeballs, I owned the machine. If you don't see it, great. Not a problem for you. We can't just sit here arguing about what one sees and the other doesn't. It's all in our personal perception.