A position associated here with Ashʿarī theologians does not regard pardon as an intrinsic rational impossibility. Yet once revelation states that a person who dies unrepentant in shirk is not forgiven, one cannot affirm that such pardon will occur.
The reasoning distinguishes rationally conceivable divine action from the truth of revealed divine reporting. To say that pardon is conceptually possible is not to claim that the stated outcome will occur.
The opposing argument appeals to a supposed necessity that divine wisdom distinguish the consequences of good and evil.