Israel is considered an occupying power within Gaza and the West Bank according to international law. Comparisons with Mexico and Canada are not particularly relevant, in that regard.
well, technically you're right. Since the withdrawal, Israel is the occupying power _around_ Gaza as it controls all access to the Gaza - by land, sea and air.
While i'm completely pro-Israel, in the sense that i fully support right of Jewish people for their state (where it is now, whatever way it happened, it has already happened), i can't understand while the same standard - the right for their own state - isn't applied to Palestinians, nor by Israel (themselves being huge beneficiary of such a right) nor by the rest of the world. Palestinians' hate toward Israel can't be a valid reason to deny their own state to Palestinians as for example nobody denies the right of statehood to Iran who officially hates Israel, nor such right was denied to Egypt back when Egypt waged a war against Israel.
It probably seems a bit abstract for americans or europeans, but it's fundamental to the people risking their lives on it.