Ironic, right? So many religions preach loving one another, but so few actually practice what they preach. When people join together to worship might it be because they feel there is safety in numbers, and if you need to gather together to be safe then doesn't that imply that there is an enemy? That would mean that it is only safe to love those who are in your group, while those outside the flock must be dangerous.
This is the great mistake of religion.