Why did many Hongkongers pre-1997 prefer getting Canadian citizenship?
New Canadians from China may correct me, but I believe that much of the original Chinese population in Canada was Cantonese, making it a more culturally comfortable destination than others. I do not have a handle on the origin of Chinese immigration in the US but it's reasonable to suspect that it's not from a British possession. And since immigration has been going on for a while, they might have family here, making it even more welcoming.