Those aquired (sic) skills were provided by the Australian taxpayer. They shouldn't be allowed to potentially be used against them when it suits the back pocket of the beneficiary.
So by your logic any engineer, doctor, scientist etc who gained their degree in Australia before university fees were tied to students should not work overseas as their qualification was paid for by Australian taxpayers? In particular they should not go to a potential "enemy" of Australia to build bridges, cars, trucks, help provide medical care etc
Good luck with that.