I agree.
A bio-weapon would have to hit the other guy harder than it hits you. Since China is the #1 suspect if it was man-made, and China is the hardest hit, it does not look like bio-warfare.
If this turns out to be man made, then I would suspect an accidental release of something that was being researched. The research could have been for possible weapons creation, but it could also have been for benign purposes. Either way, China would NEVER admit it was responsible.