Back when I played Overwatch, Mei was my favourite character, and even if her voice actress supports those shitty views, it's ameizing that the HK protesters are using her image like this, fuck Activision Blizzard.
That part of the point I believe. Some people were hesitant at first to do this because it would no doubt put the voice actress in an uncomfortable position where she is forced to publicly support the government and speak against the hong kong protests in order to save her career. When people realized that she was already super nationalist without being put in any kind of uncomfortable position, they felt much more comfortable.