To many Pixels is counter-productive!

When there are more pixels than there are photons reaching the image plane this might perhaps be true.

For a very peculiar definition of "quality". It is not defined explicitly, but implicitly understood to be pixel level noise.

Which is a very weird way to look at "quality", since if all photons were individually recorded the image at 1:1 would look like a noisy mess with zero detail (worst possible quality according to that site) while the photo viewed on a screen would have marvelous, fantastic, today unheard of detail, resolution and lack of noise (best possible quality).

Thus something must be amiss in the premises that site uses. Perhaps they know not of what they speak? SIWOTI!

Jesper