Moses was a bad card reader (spoilers)
So he read cards according to the mom's tapes - you would think he saw something about don't get the white lady pregnant because her husbands gonna kill you then in revenge 20 something years later an innocent girl will die just so your dead baby will take over her.
And that's another stupid thing. Moses was dead. The mom was dead. Black Jessabelle was dead. Shouldn't they all have been happy and dead together if they were ghosts and messing with White Jessabelle? Now Black Jessabelle is white Jessabelle and alive again so she's not with her parents anymore. I guess when they did the vudu spell they didn't know they were gonna die before Black Jessabelle could be brought back?
And the timing. 20 something years for this spell to work? Why didn't it happen literally ANY time up until White Jessabelle left for college? And only the black cook saw ghosts in the house meanwhile the ghost wanted nothing to do with her it was White Jessabelle she wanted? Lazy writing.