An online comment suggesting disused oil refineries be repurposed as "makeshift concentration camps" had been reported several times over the past week but still remained live, Dor Foundation chief executive Tahli Blicblau told the inquiry on Tuesday.
She detailed dozens of times witnesses were targeted with sexually degrading abuse, often incorporating anti-Semitic slurs.
"Where do you live so I can firebomb your car? You Jewish whore," read another comment about a woman who had posted about her royal commission submission in May.
Commissioner Virginia Bell intervened at the time after witnesses from a first public hearing block were targeted, warning any intimidation attempts would be prosecuted.
A northern NSW-based neo-Nazi was later charged for allegedly sending intimidating emails to one witness.
Ms Blicblau joined with Jewish Labor MP Josh Burns in calling for better safety measures on social media.
Mr Burns said criticism of specific Israeli policies or Australia's actions in the Middle East were "fair game" and even encouraged as a sign of people enacting their democratic rights.
But he condemned abuse being levelled at Jewish Australians because of those policies.
An "us and them" narrative, suggesting all Jewish Australians were loyal to the state of Israel and its actions in Gaza, had emerged online, he added.
"A lot of the commentary directed at me suggests somehow I am celebrating ... the death of Palestinian kids.
"That is absolutely not the case," he said.
"It's a complete dehumanisation of Jewish people."
Online rhetoric led to real attacks, including when Mr Burns was awoken in the dead of night after his workplace was targeted in June 2024.
"I felt almost guilty," the Melbourne MP said.
Anti-Semitic slurs had been written across the facade of his electorate office and an image of his face had horns spray-painted on it with the words "Zionism is fascism" inscribed in red.
Windows were smashed and fires were lit in telecommunications pits outside the building, causing hours-long outages for surrounding businesses.
Families who lived in nearby apartments, including one with a newborn baby, were evacuated at 3am.
It was the moment he knew the "goldene medina" - or golden land - was over for Jewish people in Australia, which had previously felt safe for generations.
"I felt like we were lost," Mr Burns said.
"How was this part of the democracy that we all (work for)? How was this going to solve anything in the Middle East?
"All it did was cost $100,000 to fix it and scare a lot of people."
Online anti-Semitic abuse has also been spewed at his non-Jewish partner, Victorian Legislative Council member Georgie Purcell, with a "layer of misogyny" on top of it.
"To see someone cop this sort of abuse (just because they are with you) - it's devastating," Mr Burns said.
Another witness, violinist Ben Adler, said Australian creators and art venues had bent to boycotting campaigns run via social media, which deplatformed Zionist artists.
He said a Victorian regional folk festival that had invited his band to headline quickly tried to rescind its invitation after the October 7, 2023 terror attack by Hamas on Israel and subsequent Israeli bombardment of Gaza.
"The path of least resistance for (the music festival) was just to remove the Jews from the public space to prevent any kind of outrage boiling over on social media," he said.
For the next fortnight, commissioners will be trained on the role of media - particularly the ABC and SBS - and the nature, prevalence and drivers of anti-Semitism and other hate speech on social media.
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