What is halachic rationale for separate Passover dishes?

Question

Why separate dishes for Passover? I understand milk and meat dishes. I understand how hot and sharp can transmit treifness, how "noten ta'am l'fgam" works (I think). It all makes sense.

But what is the halachic rationale for thinking that you need separate Pesach meat dishes (from every day meat dishes) and separate Pesah milchic dishes? Is this just some super humra? From when and from whom? By what reasoning? I've never heard it argued that hametzdich things like wheat and oats impart any flavor or even any "essence" into an absorbent material. Did I just miss that? Can someone explain, hopefully with a source or two to consult? I feel like I must have missed some basic halachic / physical / metaphysical principle.

Answer 1

Chametz is getting absorbed in the same way than milk and meat are. The reverse would be surprising. Why would meat and milk be absorbed but not chametz? (see this explicitly stated in third paragraph here)

Therefore one cannot cook in the same dishes since chametz is not annulled in sixty (and in any case we don't use that rule before the fact). In older times, people would kosher their dishes for Pesach (most often by immersing them in hot water). With modern wealth and convenience it has become easier to use separate dishes since they are so cheap.

For more see here, here and there.