They are referring to the Blitzchung incident, when China illegally took full control over Hong Kong before their agreement to let it be autonomous expired. During the mass protests a Hong Kong esports player voiced support for the protests on a Blizzard livestream for an event and was banned from the tournament and was forced to forfeit prize money he already won: https://en.m.wikipedia.org/wiki/Blitzchung_controversy

Edit: also, disapproval of the CCP =/= dislike of/racism towards Chinese people