Joo, whose classes focus on preparing students to take the college entrance exam in mathematics, apologised for her mistake, saying it was “a slip of the tongue in the heat of the moment”.

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The debate over her comment dominated the country’s popular search engine Naver, with some netizens accusing her of racism and others throwing their support behind welders.

“Well sorry if the truth hurts, not everyone should go to university,” one user wrote. “Learning a skilled trade can pay far better in the long run and at the beginning of one’s work life. Welding as a trade is not bad a bad job, Master welders in some countries make 9 figure won income or over a $100,000 a year.

When times get lean at some corporations the welders stay and the suits & ties leave. And older better skilled workers in the trades can get better pay than the young basic skilled workers. when it comes to skilled trades.”

Another wrote: “She is racist, and have no respect for Australia and welders. And believe me it was not a slip of tongue, it was deep in her heart.”

The celebrity teacher, who has over 40,000 YouTube subscribers, shot to fame after the Google-owned platform’s algorithm accidentally made one of her lecture videos a viral hit two years ago.

Koreans are fond of standardised exams as an objective measure of one’s qualifications, according to Shin Gi-wook, professor of sociology and director of the Korean programme at Stanford University.

“The function of exams in modern Korea is that good scores from the exam add credible values to the person’s qualifications, which might be the easiest and the simplest way to secure one’s future in such a highly stratified society,” Shin said.