Before anybody jumps down my throat, I'm Manx and born a Corlett, therefore Manx since at least 937 CE. OK?
Am a bit worried about this "take my family seriosly" thing. We none of us have a right to claim ownership of anyone else - the ones who are alive, let alone those dead for years, even centuries.
So its wasn't the greatest joke ever but someone going back through generations of Manx forebears is going to find rogues, chancers, black sheep sent to IoM in voluntary exile, slave traders, smugglers, mercenaries - the lot!
That's how the Manx survived in the centuries since the end of the Viking hegemony. It's a significant part of what makes us an identifiable as a people. Whether we'd want to be seen doing such things .... well? .... but most of us are proud of our history. That's all of our history!