Are you denying they might just be ethnically Chinese?
And are you forcing their great-grandchildren to be ethnically Chinese especially if they can't hold a conversation in the language and have never been there? And did Marilyn Manson's Polish ancestor marry someone of what you quaintly call the same 'lineage'?
More pertinently, Does Marilym actually identify as Pol-Am or is someone just clutching at straws...