David just spoke barely 2 words "egg tarts", enough to upset them. They would rather he speak English than Mandarin if he doesn't speak Cantonese.
There still exists a segment of people in HK and Macau who are somehow reluctant to be associated with China or being Chinese They have this strange made up concept in their mind that HK/Macau are somehow of a higher hierarchy than China, and feel upset and embarrassed when they perceive they are being pulled down into the same lower hierarchy of the rest of China These are probably the same kind of people who feel prouder speaking a foreign language like English compared to a Chinese language like Mandarin It's really strange.