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.