HUIZHOU, China — They were exactly what China’s best universities were supposed to produce: young men and women steeped in the ideology of the Chinese Communist Party.
They read Marx, Lenin and Mao and formed student groups to discuss the progress of socialism. They investigated the treatment of the campus proletariat, including janitors, cooks and construction workers. They volunteered to help struggling rural families and dutifully recited the slogans of President Xi Jinping.
Then, after graduation, they attempted to put the party’s stated ideals into action, converging from across China last month on Huizhou, a city in the south, to organize labor unions at nearby factories and stage protests demanding greater protections for workers.
That’s when the party realized it had a problem.
The authorities moved quickly to crush the efforts of the young activists, detaining several dozen of them and scrubbing the internet of their calls for justice — but not before their example became a rallying cry for young people across the country unhappy with growing inequality, corruption and materialism in Chinese society.
“You are the backbone of the working class!” the protesters chanted at one rally, addressing workers at an equipment factory. “We share your honor and your disgrace!”
Protests are common in China, especially by workers who have nowhere else to turn in a nation without independent unions, courts or news media. But the demonstrations in Huizhou were unusual because they were organized by students and recent graduates from some of the country’s top universities, who have generally stayed off the streets since the 1989 pro-democracy movement that ended in bloodshed outside Tiananmen Square.
In the decades since that massacre, university students have generally helped advance the party’s economic and political agenda, focusing on jobs, homes and other aspects of material well-being while supporting authoritarian rule, or at least eschewing politics. As economic growth has slowed, party officials have grown more nervous about Western influences on the nation’s youth, who are more worldly and digitally connected than ever before.
But the Huizhou activists represent a threat the authorities did not expect.
Carrying portraits of Mao and singing socialist anthems, they espoused the very ideals that the government fed them for years in mandatory ideological classes, voicing grievances about issues like poverty, worker rights and gender equality — some of communism’s core concerns.
“What we are doing is entirely legal and reasonable,” said Chen Kexin, a senior at Renmin University in Beijing who took part in the protests. “We are Marxists. We praise socialism. We stand with workers. The authorities can’t target us.”
But they have. On the morning of Aug. 24, police officers wearing riot gear raided the four-bedroom apartment the activists were renting in Huizhou and detained about 50 people. As the police burst through the door, the activists held hands and sang “L’Internationale.”
Though some have been released, 14 activists and workers remain in custody or under house arrest, according to labor rights advocates. The local police accused the workers of acting on behalf of foreign nongovernmental organizations.
Since President Xi took power in 2012, the party has sought to restrict the use of Western textbooks and stop the spread of “Western values” on campus, referring to ideas about rule of law and democracy that could undermine its hold on power.
At the same time, Mr. Xi has demanded that universities expand their teachings on Mao and Marx. In May, he visited Peking University and encouraged students to promote Marxism, saying it was important for the university to “take Marxism as its surname.”
But some in the party seem uneasy about the proliferation of these groups, apparently worried that their calls for greater economic equality and worker rights could undermine China’s modern-day embrace of capitalist markets.
While only a small minority of students are involved, they represent a leftist critique of Chinese society that seems to be gaining traction on college campuses, partly because the authorities have been more hesitant to suppress it than other political discussion.
On the Chinese internet, thousands of young people participate in vibrant Maoist and Marxist chat rooms, and some have started leftist news websites, posting commentary on topics like pollution, globalization and economic theory, without much interference by censors, until recently.
This week, school officials harassed young Marxists at a half-dozen universities and prevented some from meeting, activists said. And last year, the police in Guangzhou, the capital of Guangdong Province, arrested Zhang Yunfan, the young leader of a Maoist reading group, accusing him of “gathering a crowd to disturb social order.”
Younger Chinese are often described as apathetic, selfish and obsessed with money. But Eric Fish, a writer who has studied Chinese millennials, said that the generation born after the Tiananmen Square massacre lacks the instinctive fear of authority of older generations.
“They’re more willing to go out on the street and stick their necks out,” he said. “There is not as much appreciation for what could go wrong.”
The dispute in Huizhou began in July, after Jasic Technology, a manufacturer of welding equipment, prevented its workers from forming an independent union. China allows labor organizing only under the auspices of the official, party-controlled All-China Federation of Trade Unions.
The workers said managers had seized control of their branch of the official union. Complaining of being underpaid and treated like slaves, they began to organize a petition before the police intervened and detained several of them.
The young activists learned of the workers’ plight on internet messaging apps and took up their cause, with about 40 students and recent graduates going to Huizhou, a manufacturing hub of 4.8 million people in Guangdong Province. Hundreds of others spoke out in support online — so many that several universities warned students not to go to Huizhou.
“I could not sit still,” Yue Xin, a recent graduate of Peking University who majored in foreign languages, said in an interview before she was detained. “I could not let myself be a mere internet commentator. I had to stand up.”
Zhang Shengye, 21, who graduated in June from Peking University with a degree in pharmacology, said he was inspired to join the protests by his family’s own struggles. His father, a sailor, was laid off from a state-owned firm during a wave of privatization in the 1990s, an experience Mr. Zhang described as a “financial and emotional apocalypse.”
But it was in college that he decided to answer Marx’s call to “work for mankind,” he said. Frustrated by the low wages and poor treatment of workers on campus, he and 60 other students, calling themselves the Marxist Research Association, published a report documenting labor violations.
“We share a very simple sympathy for workers and the aspiration of a better future for communism,” he said.
In Huizhou, the young activists called each other “comrade” and wore T-shirts with images of clenched fists and the slogan, “Unity is strength.” They marched alongside workers, holding banners that declared, “Forming unions is not a crime.” They staged re-enactments of the abuse the workers said they endured at the factory.
Though they identify as Maoists, the activists are decidedly nonviolent, unlike Maoist rebels in countries like Nepal and India who embrace violent revolution. Their philosophy also differs from China’s older Maoists, who largely focus on rooting out Western influences in Chinese society and are less confrontational toward the party.
The young protesters insist that they are good communists who support President Xi.
Before she was detained, Ms. Yue wrote an open letter to Mr. Xi saying that she had been inspired by his fight against corruption and his time working in an impoverished village in the countryside as a young man.
She added that the campaign in Huizhou had its roots not in foreign ideas, but in the May Fourth Movement of 1919, a student-led uprising in China that the party considers a precursor to the Communist Revolution.
Ms. Yue, also a leader of China’s #MeToo movement who spoke out against sexual harassment and assault on campus, has not been heard from since the police detained her during the Aug. 24 raid.
Friends are also worried about Shen Mengyu, one of the first students to call attention to the workers’ campaign. She was held by security officials at a hotel and is now under surveillance at her parents’ home, activists said.
Several workers at the equipment factory have also been formally arrested and charged with disturbing social order. Huang Lanfeng, whose husband, Yu Juncong, was among those detained, said the government was unfairly punishing workers while ignoring factory abuses.
“We will never give up,” she said. “We swear to fight the evil forces until the end.”
As the school year began, the activists vowed to press their campaign. Mr. Zhang and others staged a rally in Mao’s hometown, Shaoshan, on the 42nd anniversary of the Chinese leader’s death this month, and called on the government to release their friends. The police broke up the protest and briefly detained Mr. Zhang, who was also held and released after the Aug. 24 raid.
Mr. Zhang has circulated a petition calling on the party to punish local officials. He wrote:
“We are here because we are deeply aware that what we do is legal and just.
“We are here because we want to repay the workers with what we have learned for so many years.
“We are here because we don’t want to believe that dark forces can laugh malignantly in the world we inhabit.”