Sheep Go to Heaven - Cake

I share a certain twistedness to my sense of humor with the folks of Cake. As a case in point, consider Sheep Go to Heaven. It's one of their more musical songs, more singing than speaking (although none of their tunes requires perfect pitch by any means). The song could just as well be called The Grasshopper Responds to the Ant, considering the theme. If you take nothing else from the song, take the puzzle of why they claim that "sheep go to heaven, goats go to hell" and what the heck a gravedigger is doing with those forceps.