"Throwaway lines about barbecue and cuddly animals and planets in retrograde are, naturally, not throwaway at all, a point the script makes comically obvious wh

"Throwaway lines about barbecue and cuddly animals and planets in retrograde are, naturally, not throwaway at all, a point the script makes comically obvious when Franklin, who uses a wheelchair, asks his sister Sally, the only youth who’ll survive, if she believes in astrology. She replies, “Everything means something, I guess.”" I don't understand how this makes the "planets in retrograde" mention "comically obvious?