Why does DPR care about per-pixel sharpness?

I've noticed that the DP Review staff have placed some importance on per-pixel sharpness when doing camera reviews. They have always made an effort to comment on the per-pixel sharpness, even when the cameras being compared have different amount of megapixels. My question is:

Why?

I would think that only measured resolution would matter; per-pixel sharpness shouldn't matter at all. For instance, DP Review listed as one of the 50D's cons: Per Pixel Sharpness is not as good as the 40D's. But since they already measured the 50D's resolution to superior to the 40D's... why would it matter if the per-pixel sharpness is lower? When viewed at the same size, the one with a higher measured resolution will always appear sharper. If the measured resolution of a camera is higher, it should NOT matter in any way if its per-pixel sharpness is lower.

Per-pixel sharpness is utterly meaningless except in cases where cameras of equal number of megapixels are compared. So why does DPR bother comparing per-pixel sharpness between cameras of differing resolutions? Why does it matter if the D700 has a better per pixel sharpness than an A900... if the A900 has a measured resolution that is ridiculously far above of the D700?

I think this is a perfect example of pixel-peeping for the sake of pixel-peeping, even when the results have no relevance to any real-world or practical application whatsoever.