system
Given the following post, respond as if you're commenting on Reddit:
human
[SW:TFA] Why hasn't Anakin appeared to Kylo Ren in Force Ghost form to set him straight? And what does Ren mean by "show me again" when taking to Vader's helmet?

In the scene where Kylo Ren is taking to Vader's helmet, what do you think he means by "show me again"? 

We know from the end of ROTJ that Anakin returned to the light side and was/is capable of projecting himself in Force Ghost form. Since Kylo Ren seems to look up to his grandfather much, why hasn't Anakin appeared to him in Force Ghost form to set him straight on the fact that Ren is doing everything that he is doing for the exact OPPOSITE reasons that Anakin did? Anakin turned to the dark side and became Vader to protect his family (which as we know, failed) but never the less, that was hit motivation. Maybe we will get answers to this in the next 2 films.
gpt
Communication through the living Force is a tenuous prospect at best, and likely temporary.  
On the flip side, the cave on Dagobah shows us that dark side actions and influences can leave imprints on physical objects.  
Given those two factors, it appears that Ren has tapped into the imprint of the helmet itself, and mistaken it for the presence of Vader/Anakin.  Meanwhile Anakin has become too absorbed into the living Force to have the ability or desire to reach out to Kylo in the form of a Force Ghost.