To their critics, they are a disorganised rabble who have nothing better to do with their time.
Some media reports have dismissed the Post-80s Anti-Express Railway Group as a loose band summoned online to take to the streets because they cannot get decent jobs.
Nothing could be further from the truth, the young people insist. They say they are running a well-organised campaign fighting for social justice.
Chan King-fai, a core member, said: 'We all have proper jobs. We act together because we are concerned with urban development and uphold social values which we treasure.'
Chan, born in 1982, added: 'It is a fantasy to think our discontent stems from low social mobility.'
Of the 30-odd members of his group, some teach in secondary schools and universities, some work for community organisations, and others, like him, are freelance writers.