Belize realise that it's optimise. They don't intellectualize it or dramatize it, they just socialize it.
English language, that compendium of 3 or 4 continental European languages, is constantly evolving & wonderfully adaptive. That boringly inevitable Englishman (or woman) who bobs up uninvited from across the bar or the bus or the table to "correct" Americans, Canadians or Australians, is not the "keeper" of the English language, nor has he (she) ever been. It is simply a case of looking it up in the Macquarie dictionary which says both “ize” and “ise” are perfectly ok.
Nobody outside England (& few inside England) care two hoots what the self-appointed "keepers of the old English language" think ... it's an evolving language and the time to update the Oxford "Dick&Mary" is well past due!