I have.

Different ethnic groups carry different genes. You know how you sometimes see headlines like "DNA of 2,000-year-old corpse in the Himalayas analysed; he turns out to be Greek"? So apparently some ethnicities have some genes that others don't; otherwise they couldn't know that.

Make a bioweapon that targets people with genes that your ethnic group doesn't have, and you've made a bioweapon that targets only people of other ethnic groups.

How would that even work? There isn’t a gene for Chinese citizenship that would impact any disease or illness.

…I’m unfortunately assuming the poster is making a bad-faith reference to COVID-19. Some conspiracy theorists have been labeling it a bio weapon and ignoring the deaths from the initial outbreak.