No, Hong Kongers should not commemorate the Chinese victory in the Sino-Japanese War (1937-1945).

The Sino-Japan War (1937-1945) did not involve Hong Kongers indeed, though Hong Kong, then a British colony, was under Japanese occupation from 1941 to 1945.

Hong Kongers suffered during the Japanese occupation period (1941-1945) mostly because the then Chiang Kai-shek Chinese regime imposed an embargo upon Hong Kong, and in consequence many Hong Kongers starved to death.

Beijing regime uses the 60th anniversary of the Chinese victory in the Sino-Japanese War to persuade Hong Kongers into believing wrongly that Hong Kongers are Chinese nationals.