I guess the difference is that the information that is revealed by the ghosts is never something that could massively change the outcome of the entire plot like what you described. In Luke’s case, it if anything only makes the potential for him to fall to the dark side greater because Vader is able to exploit is newfound connection with Leia. And in Rey’s case, it only provides her further justification as for why she should face her fears.

I will agree that the script writers were definitely only considering the emotional impact of the reveals in this movie, not whether they make sense logically based on what came before.