The troublesome explanandum in Plantinga's argument against naturalism

Intending to have a constructive dialogue with the combination of evolutionary theory (E) and metaphysical naturalism (N), Alvin Plantinga's "evolutionary argument against naturalism" (EAAN) takes the reliability of human cognition (in normal environments) as a purported explanandum and E&N as a purported explanans. Then, he considers whether E&N can offer a good explanans for this explanandum, and his answer is negative (an answer employed by him to produce a defeater for N). But I will argue that the whole EAAN goes wrong by assuming that R is a qualified explanandum crying out for scientific explanations, since it cannot meet either of the two criteria for any scientifically qualified explanandum: Realizability Criterion and Informativeness Criterion. Hence, EAAN is simply setting a task that E&N, as a scientific theory, will not care at all. Therefore, EAAN cannot substantially shake E&N.