Some context would be nice here.
Quoting: Anonymous Coward 77940105 My recollection is, that the hymn is familiar from a musical or a movie that was popular in Hong Kong, and it was sung during some earlier protest.
I think I wondered the song choice earlier and looked in to it, and that was the context.
I gotta say the reason for the protests is peculiar, the demonstrators didn't approve a law that would allow extraditing criminals to Mainland China, Taiwan or Macau. Strangely enouhg Hong Kong has extradition treaties with UK and The USA; Snowden was in danger to get extradited from Hong Kong.
And also, there was no democracy in Hong Kong until it returned to China; the British colonial overlords ruled.
The protesters could try to advance their cause democratically, via voting in elections. Maybe their causes are not popular enough?
couple of trivia questions:
how many official political parties exist in Communist China?
what party is banned in Hong Kong?