I've heard YouTube make statements to the extent of, and I'm paraphrasing "we do the opposite of taking you down the rabbit hole" in regards to any conspiracy related content. A bio-weapon implies conspiracy implicitly at least to some extent.
China Uncensored is by no means a "conspiracy" oriented channel. They focus mostly on geopolitics and financial issues, mostly related to China. There is no good reason Youtube should be censoring them, they aren't saying anything even remotely controversial, that is unless you are Winnie the Pooh.