Romans believed that their state was based on the Pax Deorum principle: if the Romans acted in accordance with the divine commands, then the gods acted in their favor. The greatest obstacle for the Romans to maintain this principle were Christians.
Christians, either considered the deities of the Romans as demonic beings or rejected them at all. This was against the Roman raison d’etat, which required the recognition of traditional Roman gods as well as the divinity of the emperor himself.
If the Romans would agree that Christians can only confess their god, they would be exposed to the anger of the official deities of the Empire. What is worth emphasizing, usually the Romans put Christians in a “comfortable” situation. Christians could have avoided torture and death if they recognize the traditional Roman deities. Some Christians did not agree to such conditions and preferred to die in the name of the only God.