Beijing, Nov. 26 -- Don't mess with China and its growing cadre of powerful luxury consumers.

Dolce&Gabbana learned that lesson the hard way when it faced a boycott after Chinese expressed outrage over what were seen as culturally insensitive videos promoting a major runway show in Shanghai and subsequent posts of insulting comments in a private Instagram chat.

The company blamed hackers for the anti-Chinese insults, but the explanation felt flat to many and the damage was done. The Milan designers canceled the Shanghai runway show, meant as a tribute to China, as their guest list of Asian celebrities quickly joined the protests.

Then, as retailers pulled their merchandise from shelves and powerful e-commerce sites deleted their wares,...