What Do You Think About the Spirituality of the Church?

In seminary, a guest lecturer said that the doctrine of the spirituality of the church is one of the greatest heresies in the an history of christianity. He thought it was to blame for slavery and other things where the church wasn't speaking out against injustices as they should have. In his view, we need to be very careful in the exercise of our power over others. The word of god has given us weapons which are not limited by political or social circumstances. We cannot tell people how to vote on issues such as abortion without being politically correct.