This must have been written by someone that just learnt about sampling theory and thought "aha! Pixels are samples!" without actually thinking about real life.

This must have been written by someone that just learnt about sampling theory and thought "aha! Pixels are samples!" without actually thinking about real life. This was written by one of the fathers of computer graphics. chriswarbo was completely right, but was downvoted anyway. You are conflating displays of pixels with calculating the color of each pixel that goes into an image. Each pixel in a rendered image is weighted average using a specific filter over an area around a pixel. If you treat that as a square, you get a 1x1 box filter which is terrible for anti-aliasing. You can try this by playing with renderer settings so you understand what he's talking about in the context he was talking about.