I think Book Scientists call things "darkly comic" to show the rest of us plodding numbskulls that they see some sly, sophisticated humor in these books. Stuff that we rouge-necks miss because we don't listen to NPR or go to symphony concerts and plays, &c.
Problem is, they call everything except Mein Kampf, "darkly comic".
Problem is, they call everything except Mein Kampf, "darkly comic".