Is the story true about the Muslim man who criticized a Christian, then lost his faith, then fell in love with and married a Jewish woman? And does this mean that it is impermissible to criticize Christians or to harbor hatred towards them?

Some people might invent or embellish stories out of ignorance or personal desire, and then these stories are transmitted as true. Storytellers are censured for their fabrication and for claiming the impossible. The aforementioned story is false and advocates against criticizing a Christian, which contravenes the religious obligation to clarify the falsehood of their religion and the distortion of their scripture. Disavowal of disbelief and disbelievers is a fundamental principle of the religion, as Allah Almighty says: "There has already been for you an excellent pattern in Abraham and those with him, when they said to their people, "Indeed, we are disassociated from you and from whatever you worship other than Allah. We have denied you, and there has appeared between us and you animosity and hatred forever until you believe in Allah alone." Criticizing the religion of Christians is a means of inviting them to the truth, and the Qur'an is explicit about the invalidity of their beliefs. Assuming the story is true does not mean that Allah punished the Muslim for criticizing the Christian; rather, it could be a punishment for other sins, as criticizing Christians is permissible and beneficial for them.