Whether you're Christian, Jew, or agnostic, Muslims expect the default position will be that you will revile Pagans. Therefore when a Muslim presents his case for Islam, he takes it for granted that you will already affirm the position that pagans are disgusting and he will work on that basis. Nothing stuns a Muslim to the spot more than someone saying "What's wrong with Pagans?" or "I don't mind pagans". You're expected to know innately that pagans= bad and evil.
