What the fuck are you even talking about? Not only is “-ize” not exclusively American English, not only do you have no evidence this person is American, not only is “-ize” not even an Americanism, and not only was “-ize” in use over a century before Britain established the colony of Virginia, but “-ize” predates “-ise”.
Maybe stop trying to prescribe what the “proper” suffix is when you don’t know shit about it.
What the fuck are you even talking about? Not only is “-ize” not exclusively American English, not only do you have no evidence this person is American, not only is “-ize” not even an Americanism, and not only was “-ize” in use over a century before Britain established the colony of Virginia, but “-ize” predates “-ise”.
Maybe stop trying to prescribe what the “proper” suffix is when you don’t know shit about it.