Taking as granted that “China” is systematically behind this crisis is so helpful to shift the blame from decades of failed prohibition-based drug policies in the US.
Is it possible that the Chinese government is just avoiding acting? Of course, because they’re dealing with an internal problem of an adversary state that would do exactly the same (and has done the same) if the roles were reversed.
Moreover, these drugs trades are just an over-optimization of a free market offer, and work exactly like a perfectly tuned capitalist device.
Blaming the opioid crisis on China is a very convenient scapegoat that gives America the opportunity to watch away from the profound root causes hidden in its own society that made it possible.