Final answer:
While the reference material does not directly answer who 'Pi' cannot tolerate, it does highlight that atheists and agnostics can be moral individuals. Therefore, based on the context, 'Pi' may not tolerate 'fanatics' due to their potential for intolerance.
Step-by-step explanation:
The question refers to a scenario where 'Pi' can tolerate atheists but not another group. Considering the context of the reference material provided, the answer seems to refer to perspectives on belief and nonbelief. Atheists are individuals who do not believe in a divine being or entity. Agnostics are those who think ultimate reality, such as the existence or understanding of God, is unknowable, while neither atheists nor agnostics necessarily lack morality. The given options are agnostics, fanatics, skeptics, and nihilists. There is no explicit answer provided in the reference text, but given the positive light shed on atheists and agnostics, it would be reasonable to infer that 'Pi' may have difficulty tolerating 'fanatics' since fanaticism often implies unyielding enthusiasm for a religious or political cause, potentially leading to intolerance of other views.