> I think it's perfectly reasonable and even necessary that ill-founded but hard-to-disprove theories such as the lab leak theory at the time are examined critically,

There's nothing ill-founded, it was then and is now the most reasonable and plausible explanation for the outbreak. You can do the same back of the envelope calculation today that I did 2 years ago, and nothing has made it less valid:

1. There's 100 cities in PRC with >1 million inhabitants.

2. There's one (1) lab in PRC doing work on bat viruses.

The probability that the outbreak happened in the same city as the one with the lab by pure coincidnce is therefore about 1%.

That's not a proof, that's not a definite argument, that's just evaluating how plausible the hypothesis is. You can tweak the values to be more charitable if you want, say note that Wuhan is a large city and we shouldn't count smaller ones, or point out that there might be a few mor labs doing the same kind of work but with less prominence. That merely lowers the lab leak's plausibility to 50%. I.e very plausible.