It's entirely possible that the people ordering the culls and the people carrying out the scientific investigations are different and don't talk to each other. From what I've heard, the wildlife trade was shut down very quickly after the outbreak was discovered. This is a bit like the Huanan market: it would have been scientifically valuable to keep it as-is and do a thorough study, but once the authorities discovered there was an outbreak there, they immediately ordered it to be closed and decontaminated - which makes sense from a public health point of view.
Anyways, there has been a lot of extremely valuable research published over the last year+ by Chinese researchers on the origins of the virus (we now know a lot more about the family of viruses that SARS-CoV-2 belongs to, for example), and I think progress will continue to be made.
Regarding the researchers, there were videos by some people in China who later vanished. I know that China is usually China, but that doesn't exactly make me trust them more.