a simpler answer might be the talmudic dictum: "one who says 'I will sin and repent, sin and repent, and Yom Kippur will atone for it all", Yom Kippur does not accomplish atonement for him.

Under ordinary circumstances, if one repents (regrets the act, confesses it to God, resolves not to do it again, and when confronted with a similar situation does not sin again), Yom Kippur (the Day of Atonement) atones for hir. In this case, it's not sincere repentance, so the rest of the process can't complete either.