why do you think jerry decided not to sell the chocolate even after this assignment was over

There was nothing good about selling chocolate for Jerry. Jerry, Goober, and even Archie are all confronted by seemingly insurmountable authority figures, be it the school, Brother Leon, or The Vigils. The chocolates become a metaphor for competition, identity, violence, and abuse. The Vigil's effective fear tactics have kept the student body in a state of unquestioning obedience thus far, and the fact that Jerry defies them by refusing to sell the chocolates (a negative action) shows that positive actions are ineffective against mob rule. Ultimately, however, Jerry's determination to negate The Vigils' authority has grave consequences for him, as he is severely beaten twice. Jerry has no love for selling chocolates when his assignment is over.