Because it was probably quite different for them. British colonialism wasn't the same everywhere. They probably had much more prosperity and freedom,maybe even respect and certain equality with the Brits there,rather than for example the subcontinent or Malay had with them. When you see flocks of Hong Kongers leaving right before the handover and 20 years later,many of them protesting with hundreds of British Hong Kong flags in the streets,that means something. And no idiotic "oh they trying regime change american dog want stirr trouble" PRC excuses will convince anyone.