Value Points :
Because of the feeling of guilt on hitting the snake / both were harmless and hit/killed for no reason / scared of the consequences.
Detailed Answer :
The poet hits the snake with a log. The snake writhes in pain and disappears through a hole. The poet is immediately reminded of the Albatross who was killed by the Mariner for no reason. He feels guilty on hitting the snake because it had not tried to harm him. He is scared of the consequences.
