The death this week of the South Korean singer and actor Sulli has turned the spotlight on the darkest corners of the highly pressurised K-pop industry and sparked anger over the failure of management agencies to protect their stars from the menace of “toxic fandom”.

Sulli, a former member of the group f(x), had spoken publicly about her mental health problems and shock at her death has led to calls for greater support for performers. Authorities said she was suffering from severe depression and are investigating suicide as a possible cause of death.

Sulli, whose real name was Choi Jin-ri, was one of a growing number of female South Korean singers and actors to have been targeted by online vitriol, often from anonymous male fans enraged by their idols’ refusal to conform to social norms.

Her “crimes” had included live-streaming a drinking session with friends and her decision not to wear a bra in public. She also revealed that she was in a relationship at the zenith of her singing career, defying the industry’s carefully crafted image of young female stars as sexually desirable but inexperienced.

She smashed other taboos, too, hosting a TV series about how online abuse had contributed to her anxiety disorder and social phobia, in a country with a strong cultural resistance to discussing mental illness.

“She expressed her views about what was intrinsically wrong in our society about how female stars are supposed to behave,” said Prof Yunkim Ji-yeong, an expert on Korean gender issues at the Institute of Body and Culture at Konkuk University in Seoul.

The messages of sympathy that flooded the internet after news of Sulli’s death emerged on Monday also criticised the culture of South Korea’s intensely competitive entertainment industry and the toll it takes on young performers.

Promising stars are put through a gruelling training schedule as they pass along the conveyor-belt production of new girl- and boybands. Young stars are subjected to strict controls over their private lives, including bans on dating, restrictions on mobile phone use and an expectation that they will sacrifice their health to achieve the desired image.

“I think a day where [people] would be ashamed of the K-showbusiness will surely come,” one user wrote. “I think an industry that makes money by [making people] sing, dance, undergo plastic surgeries and go on a diet to please the gaze of others since they are teenagers should really go bankrupt.”

Sulli was 11 when she began her career as an actor, before making her K-pop debut in 2009 for f(x), who quickly became one of the country’s most popular girl bands.

“Many celebrities who debuted at young ages suffer from depression and anxiety as they have to live in the public eye. They can be vulnerable if they get too much attention,” Park Jong-seok, the head doctor at Yonsei Bom psychiatric clinic in Seoul, told the Korea Times. “They go through adolescence without experiencing genuine friendships and stability with peer groups.”

A number of entertainment stars have killed themselves in the last decade. Jang Ja-yeon, a popular soap star, took his own life in 2009, leaving a seven-page letter in which she claimed she had been the victim of sexual abuse and exploitation by influential politicians, business and newspaper executives and industry figures.

The K-pop star Jonghyun, whose real name was Kim Jong-hyun, killed himself in December 2017; the singer and actor Goo Hara, once part of the girl band Kara, apologised to fans after being found unconscious at her home earlier this year.

Kwon Ji-an, a singer and painter better known by her stage name Solbi, was subjected to cyber-insults in 2009 while a member of the K-pop group Typhoon, after being wrongly identified in a sex video that was widely shared online.

Sulli’s death has intensified demands for government action against bullying on popular internet portals where users are able to comment anonymously.

The website of the office of the South Korean president, Moon Jae-in, was flooded with demands this week that users be required to register their real names before commenting. The national assembly will reportedly begin debating a bill, already dubbed “Sulli’s law”, later this year.

South Korean politicians have previously shown a willingness to tackle other forms of abuse with the enactment this year of a law against workplace bullying – known as gapjil – with persistent offenders facing a prison sentence of up to three years or a maximum fine of $25,000.

The public’s appetite for action against those who torment celebrities online is also growing. A poll this week by Realmeter showed support for new legislation at almost 70%.

“Freedom of expression is a vital value in democratic society, but insulting and hurting someone else’s dignity is beyond that limit,” said Lee Dong-gwi, a psychology professor at Yonsei University in Seoul. “There need to be far harsher penalties for those who violate that law.”