Out of ignorance, what law did they break and are they likely to be charged with?
We have racial vilification laws that cover stuff like that.
New South Wales: Anti Discrimination Act (1977)
In New South Wales racial discrimination is unlawful in the areas of education, employment, the provision of goods and services, accommodation and registered clubs. For the purposes of the New South Wales Act, "race" includes colour, nationality, descent, and ethnic, ethno-religious and national origin. The Act also makes it unlawful to discriminate against a person on the ground that the person has a relative or associate who is of a particular race.
The New South Wales Anti-Discrimination Act also prohibits racial vilification. Racial vilification may in serious cases amount to a criminal offence. Racial vilification under the New South Wales Act is any public act which is capable of inciting hatred towards, serious contempt for or severe ridicule of a person or a group of persons because of their race.