why was the mariner made to suffer for killing the albotross?

The Mariner is punished because he committed an act of violence against nature, and he suffers both mental and physical punishment in relationship The Ancient Mariner suffers punishment both mentally and physically in response to his crime. The Mariner's is punished directly by the spiritual and natural world for his crime.

Physical punishment includes the deprivation of food and water;

"Water, water, every where, Nor any drop to drink."

The heat of the sun; "Down dropt the breeze, the sails dropt down..." "All in a hot and copper sky, The bloody sun at noon."

The Spiritual world punishes the mariner by making him responsible not only for his won punishment, but for the fact that his crew must suffer with him. This punishment fills the Mariner with guilt, not only for his murder of the albatross but for the deaths of his men as well. His punishment comes from watching these men leave the world and knowing he won't escape so easily. Eventually, he becomes like the living dead, only finding escape after sharing his tale and praying for forgiveness.