Because the name Purple Dragon Knights is evocative? Because the idea of knights from an idealised feudal kingdom - like Cormyr in FR, or Furyondy in GH - is a very well-established trope for FRPGing?
Empathy is a response to others' suffering.
No one suffers because WotC publish a book in which imaginary names and beings are in different relationships to one another from the relationships that were talked about in a previous book.
Eg in the Claremont X-Men comics, Wolverine and Rogue do not become X-Men at the same time; Wolverine is already an X-Man when they meet. In the first X-Men movie, they do become X-Men at the same time. Thus, the movie differs from the comics in the way it presents these characters and their relationship.
Maybe some people like the comic version better than the movie. Maybe for some its the opposite. I know that at least one person - me - has enjoyed both.
But notions of suffering and empathy are completely inapt when we're talking about thiese sort of responses to serial fiction.