-ize is perfectly good English, Thunder, even in Australia (but not for some words, like 'advise'). It even used to be preferred, decades ago.
Where the septics start to make things odd is -yze endings (e.g. analyze), which is a dialectal spelling peculiar to them. Some of Webster's silly ideas didn't catch on, though: hed, bilt, groop and tung, to name a few.