That's an issue with Australian law, not Apple. You can also buy such devices overseas.
Bought my iPhone 6S from Apple in Ausralia: ID required under Australian law.
Very likely the person also bought a phone with a sim/service, hence being asked for ID (under Australian law.)
My guess is that they paid online for in-store pickup, and Apple asked for ID to confirm they're the one that made the purchase. In which case that's an Apple thing, not a government thing.
Bought my iPhone 6S from Apple in Ausralia: ID required under Australian law.
Very likely the person also bought a phone with a sim/service, hence being asked for ID (under Australian law.)