For people doubt about the OP's story, I really don't see any flaws. (S)he mentioned the reason for urgent process is to apply UK youth mobility visa with Canadian citizenship in order to get a good job opportunity in UK. For people don't understand what's UK youth mobility visa, it's a working holiday scheme for young people under 30 to work in UK no more than 2 years without any employer sponsorship and it's not extendable and convertible. So that means it's impossible for OP to live and work in UK for more than 2 years, unlike other people who get jobs and work visas which can be extended forever in gulf countries or even converted to PR in USA. So OP is not breaking tie with Canada and that's the first reason why CIC can consider her/his urgent request. Also because only a few nationalities are eligible for UK youth mobility visa, Canada is one of them, but OP's native China is not, that's another legitimate reason CIC can consider why OP has to have Canadian citizenship urgently. It's also different from other people who want to apply for work visas of gulf countries or USA as these visas don't limit nationalities.
In summary, OP has to have Canadian citizenship (her/his native citizenship cannot) to have a maximum 2 years great job opportunity in UK, it's total valid reason to get urgent process.
Most other people just want to leave Canada forever ASAP, have work visas (on their native passports) and permanent jobs in other countries, it's not valid reason to get urgent process, even disqualify their applications under "intent to live in Canada" rule before C-6.
I understand why OP is excited to share her/his story on the forum, as it's a rare case and even she/he is surprised about the result, now she/he has Canadian citizenship, UK youth mobility visa and a great 2 years internship waiting in UK to advance her/his career then probably she/he will return to Canada after 2 years to have much better career opportunity. I guess OP is a young graduate, I should congratulate all your achievement so far.