Jack Dawson was being metaphorical He isn t royalty of any description he s a peasant He isn t even a king of peasants If I had a dog and my dog had a child and my dog s child had a pet that would be Jack Dawson Lord Voldemort however is a Dark Lord which is to say a warlord with magical powers Warlords actually rule people thereby qualifying them for the title of Lord Furthermore no I don t know you in real life you just remind me of someone I used to know