Friends and Protectors
"O you who believe! take not Jews and the Christians for your friends and protectors: they are but friends and protectors to each other. And he amongst you that turns to them (for friendship) is one of them. Verily Allah guides not a people unjust." [Qur'an 5:51]
This reads like something that a current day Imam might say. The Jews and Christians care nothing for you, so shun them. Christians know this to be in direct opposition to any Christian teaching, but since it is written in the Qur'an, Muslims have no choice but to abide by the ruling.
This is part of the reason I have the feeling that much of what I am reading was written to keep a restive people under control. The Jews and Christians were the world powers at this time. The leaders of a different people needed to fight for followers and threaten the flock into staying put.