I've always hated this episode. It's one of the "Prime Directive = let them die" scenarios that we see again in Homeward and briefly in Who Watches the Watchers. At least in Pen Pals, they finally decide to help the people. In Homeward, Picard blatantly refuses, and Worf's brother has to force the Enterprise to save a civilization using subterfuge. And the only reason Picard did choose to help this time was that it was a cute little girl asking for help. Had it not been for that, they would have gawked while the planet destroyed itself and wiped out all the people.
Was it this episode where Picard says that the primary purpose of the Prime Directive is to protect themselves? Not to protect civilizations from interference, but to protect the Federation from making matters worse, pretty much. What harm is it for the Enterprise to stop the volcanic activity high from orbit without any person-to-person contact? Data and the girl complicated things, but ideally, the Enterprise did everything without the people on the planet realizing it.
This sends a bad message that primitive societies have no choice but to die unless they call out to the heavens for help and hope to catch an android's radio frequency.