"That's when she jumped in and took matters into her own hands ... so there is some context to it."
Following the assault, Moses turned her attention to the first victim and began yelling "that's what you get for being white," repeatedly, police prosecutor Sergeant Rachel Willemsen said.
Ms Burlace said her client denied saying the words, and thought it might have been someone else in the group.
Moses struggled while police arrested her and prompted three friends to try and intervene with her arrest.
Ms Willemsen said the groups were strangers to each other and the attack was "completely random".
It is the 28-year-old woman's first assault offence. She is a student and has four children aged between 9 months and 8 years.
She earlier pleaded guilty to common assault and disorderly behaviour.
"The court doesn't put up with street violence at this level," Judge David Cameron told her, calling the offending "totally unacceptable".
He sentenced her to 140 hours of community work.