(link)In Australia, it is unlawful to discriminate on the basis of a number of protected attributes including age, disability, race, sex, intersex status, gender identity and sexual orientation in certain areas of public life, including education and employment.
Which amounts to: you're allowed to discriminate on whatever you like, as long as it's not in this list.
Maybe it's a common vs civil law thing? There's always the claim that in civil law countries everything is forbidden unless it's allowed... I guess that applies to discrimination also.