“The injury indeed is the same, but it becomes greater by the excellence of the person. And if he who insults a king receives intolerable punishment, on account of the superiority of the person”
Not the excellence or the superiority of the person; it’s the office that commands respect.
How can the dead insult the Living One? You first have to have a relationship with someone in order to insult them.
See Belshazzar and Ahaziah.
Granted that God cannot be insulted, but that doesn’t mean He isn’t miffed at those who try.