There can be little doubt that Joseph does all of this for revenge against the brothers who wanted him dead. Of course, it also drives them to confess their guilt, but one cannot deny that revenge is the primary motive. Well, who can blame him? Being tossed into a well and screaming for help to no avail, hearing the brothers break out a picnic, would drive a man to revenge, would it not? So, does Joseph's claim about God right after his revelation sweep away these acts of revenge? I do not think so.
The second issue of the reading that I have has to do with the reactions of the brothers to Joseph's revelation of himself. If one reads that revelation with care, there is far too much of how grand and glorious Joseph has become and far too little about what his brothers are now thinking of him. Weeping and revelation are dramatic acts, but the fact that his brothers say exactly nothing to him until the very end of the scene (Gen. 45:15), and even there we are not told what they say, suggests that the revelation has not at all made things all right. And that fact is made doubly certain by what happens at the very end of the book of Genesis.
Jacob has died, and the brothers are charged with the responsibility of burying him back in the land of Canaan in the cave of Machpelah, a plot of land bought long ago by Abraham from a Hittite named Ephron. After the brothers discharge this sad duty, they all return to Egypt. Immediately, Joseph's brothers are afraid. "What if Joseph still bears a grudge against us and pays us in full for all the wrong we did to him?" (Gen.50:15). So, they lie to him, saying to Joseph that before their father died, he had urged Joseph finally to forgive all his brothers. The text says nothing about such a demand from Jacob at all. And at this statement, the very weepy Joseph weeps, but I think his weeping here has to do with his recognition that all the grand theology in the world cannot finally cleanse the nasty games of revenge that he had played against his brothers. Even now, they cannot trust him to treat them with honesty and openness. Though he tries one more great theological statement in the attempt to make it all right—"Even though you intended to do harm to me, God intended it for good, in order to preserve a numerous people" and "Do not be afraid; I myself will provide for you and your little ones" (Gen. 50:20-21)—it is just too late. Revenge is a dish best served cold, it is said, but whether hot or cold, revenge muddies all waters, clouds hopes, and destroys the possibility of community.
Thus, we are lead back to Jesus. "Love your enemies" is not at all impractical, though it is hard. It is rather the practical road to genuine community. Yes, revenge is sweet, but like all sweet things it is, in the end, not very good for you. Choose love instead, and tell Joseph to try that, too.