Mysterious Island by Jules Verne moral of the story?

Question

What is the moral of the Mysterious Island story? What message author (JulesVerne) try to convey?

Answer 1

That stronger nations must not oppress lesser ones, or there will be a terrible price to pay. Capt. Nemo was a Pole whose country was taken over partly by Russia and then oppressed in revolutions of 1830 and 1848. So he took to the sea to sink all ships of "that hated nation."