Wouldn't you do the same? Unambiguous proof that it was leaked from a lab would be ruinous to the country. Everybody would demand damage compensation. There is absolutely no upside in admitting the truth if it was so. A nation doesn't get any points for doing the "moral" thing.
That's why it is important that this is NOT about establishing historical truth with evidence. If it was human-made, we would realistically never find evidence.
The only thing that counts here is whether it is a plausible scenario or not. I do think there is evidence that this is a plausible scenario, which means that we should act to prevent something like this from happening in the future. Completely regardless whether there was a actual lab leak in the past or not.
That's why it is important that this is NOT about establishing historical truth with evidence. If it was human-made, we would realistically never find evidence.
The only thing that counts here is whether it is a plausible scenario or not. I do think there is evidence that this is a plausible scenario, which means that we should act to prevent something like this from happening in the future. Completely regardless whether there was a actual lab leak in the past or not.