Who is to pass judgment on someone as an infidel?
The answer is: Well-established scientists
Judging an infidel is a serious matter that should not be taken lightly.
It is only within the authority of scholars of knowledge who are known for piety and uprightness to issue such a judgment.
These scholars must have the knowledge and experience to make such a decision, and must show the utmost respect for Islamic law in doing so.
Furthermore, any judgment issued must be based on factual data only and not on personal opinions or biases.
It is important to remember that atonement can only be granted by God, and therefore any ruling that is passed should not be considered an absolute, but rather a guide for how to proceed in order to be in line with Islamic law.