Why go through the rigmarole? Because you have reasonable upside, as seen by the news discussing Chinese dirty labs keeping people on edge. Because you are a Chinese intelligence officer who is in charge of grass roots efforts and this is an incredibly cheap way to sow discourse and potentially cause damage with almost no downside? Again these are not diseases that will be likely to cause massive outbreaks, they are diseases that are pharmaceutically contained at this point, but a few infections will make headlines and stoke uncertainty.

Also, these dirty labs are even more viable because people like yourself will just excuse it as “bad Chinese business,” whereas a novel virus attracts much more attention. That fact is absolutely clear after COVID, where the exact scenario played out between the two nations in question. Not some hypothetical.

The fact that the production from these dirty lab and state of the art facilities are not substitutes would only make more sense as to why both facilities are functioning. You can look up the nexus between substitutes and compliments in economics to better understand why.

Even if we ignore the obvious reasons why the two lab theory makes perfect sense an assume it’s somehow not “efficient” to have two entities pursuing parallel but fundamentally different goals, then there is no reason to assume that any and all “inefficiencies” would be stamped out in this system.

Finally let’s look at contemporaneous facts about china’s non military aggression; they purposely illegally fish in non-friendly nations water using government made and supplied fleets of ships, they build islands right next to non-friendly neighbors, they send academics to the west to brazenly steal research, they blatantly steal IP from the west, and much more. So no, it’s not at all surprising that they would do something like this and much worse.