1. Gain of function is not as easy as you think.
2. Such bio-weapons are not likely because any virus released in the wild will mutate over time, and also because you cannot target "races" in the way you describe. Phenotypic traits span across geographical borders, and any attempt to do such a thing is likely to backfire.
I think if the CCP were successful in creating race targeted bioweapons it would be in their interest to convince the world that they didn't exist.
Insults, character assassination campaigns and politicizing the existence of these bioweapons would be a good way to do that. Just copy paste some of the comments here and change the name to insult anyone who thinks they exist. They could then go and kill millions and not receive any retaliation whatsoever with people praising them for their effective program of keeping the disease epidemic they created under control. Even if you got the guy who discovered AIDS and won the Nobel prize for it to say that these were gain of function viruses that incorporated HIV protein parts, you could just launch a big propaganda campaign to attack his character.[1] Much cheaper than having to fight a war.
