The dividends I earn through KWSP will be taxed at 45% as I fall under that tax bracket in Australia. As a Australian tax resident, anything I earn overseas will be added onto my taxable income. And since my taxable income will increase from my KWSP dividends, I get less benefits from the government (e.g. childcare subsidy) - so essentially I'm losing half of what I earn through KWSP.

You don't have to be an Australian Citizen to be a tax resident.