3/ this shows us that we need to change our understanding of "punishment after death":
it is something that is implied *automatically*, necessarily, by his contempt for death and the gods.
"after death" is not temporal, but means "spiritually", "concerning the soul."
4/ Sysiphos' pointless struggle is thus a direct result of his awareness and his acceptance of the meaninglessness of the world. (Note the parallels to the expulsion from paradise, for instance)