"In my view you have been pilloried more than sufficiently already ... on social media," Judge Dawson told the woman.
He noted she had been vilified through the actions of another person through social media "which appears to have gone viral throughout Queenstown".
The victim, who flew in from Sydney for the trial, told the court her face was left burnt and scarred by the incident.
The hot chocolate was "in my eyes, it was down my cheek", she told the judge.
"I was just in shock; I couldn't believe it had just happened."
The incident was sparked when the defendant's friend, Lucy Emily D'Amico, said: "There are f------ Asians everywhere. They need to go home," the victim said.
D'Amico was fined $300 last year after pleading guilty to offensive behaviour likely to cause violence.
The victim said on Thursday the comment made her "sad" but she challenged D'Amico out of social responsibility, saying such comments were inappropriate.
When she held D'Amico's arm, the victim said the defendant told her she could say "whatever the f--- she wants".
The judge, however, said there was no evidence the defendant heard her friend's comments.
The victim said the defendant told her shut up or she would pour her drink over her - a threat that was not repeated in the victim's police statement.
Judge Dawson said the defendant should not have become involved or supported her friend's bad behaviour.
"What you did, quite frankly, was brattish. It was stupid. It was impulsive."
In discharging her without conviction, the judge said the incident was a "one-off" and the consequences of a conviction would have outweighed the seriousness of the offending, which was at the lower level.
He advised the woman to "think before you act" in future.
The defendant was ordered to pay $500 emotional harm reparation by 5pm on Thursday and $130 court costs.
Earlier, arguing for name suppression, Mr Collins said an article about the incident and photo of the defendant were published before she was spoken to by police.
Referring to an earlier decision of the court, he submitted the "publicity and media attention can itself be a consequence of an offence".
The woman had future career plans in the education sector, and an assault conviction had the potential to derail that, as well as potential travel overseas, he said.
Police opposed permanent name suppression.
Prosecuting sergeant Ian Collin called the social media reaction "yesterday's news".
He said the defendant's situation was not different from the reaction to many others who appeared before the court charged with sexual offending or offending against children.
International travel should not be a reason for a discharge without conviction, so as to allow other countries to make their own decisions about protecting their borders, Sgt Collin said.
Also, the arguments over the woman's future career prospects were "too vague".
Judge Dawson also permanently suppressed the names of the victim and a witness to the incident.