I guess they needed her parents to be sympathetic in order to fuel a revenge angle for Rey. But, you’d think the Emperor would be enough of a target that it might work without that.
And just to make sure, because this movie went by too fast… is the chronology supposed to be that her parents went to Jakku and sold her to Unkar Plutt, then left in that ship we saw in TFA, then encountered the hunter, got killed, and then the hunter used their ship to go die on Pasana?