In viewing The Pearl as a parable, good and evil can be seen in very absolute terms. The family is good; greed is evil. Love is good; destruction is evil. Oppressive colonization, corrupt capitalism, and racism all go on the "evil" list, which we have to say is a tad longer than the "good" one. In this novel, the only thing that stands outside the clear evil vs. good dichotomy is the pearl itself – it simply reflects what is around it. That the pearl ends up reflecting evil is an indication of The Pearl’s grim view of the world.
Because The Pearl is so entrenched in its overly-simplistic views of good and evil, it is incapable of serving effectively as a critique of society’s flaws.