The point: Scientist says in private "A thing is possible" but in public "A thing is not all possible!"
Not the point: "A thing is possible, therefore it happened"
Note that all of this is deeply problematic, EVEN IF the truth is that the virus was a normally evolved bat coronavirus that got to Wuhan through some method that did not involve a lab in any way. The dichotomy between what they were saying in public, and what they were saying to each other in private, severely undercuts the idea that they are who the public should be trusting for advice on this topic.
I wonder how this would play out if we transposed it to any other field. If I was interviewed and asked if So-And-So had proved P=NP, I'd just say "almost certainly not" knowing that any other response would require an amount of nuance that wasn't going to be conveyed - despite having plenty of private conversations that "yeah, P=NP is total possible and it'd be interesting because...". And that's a pretty theoretical problem with immediate real world impact, and relatively little new being discovered day-to-day.
I'd be shocked if there was any non-trivial topic discussed in any field where the internal debate _isn't_ broader and more nuanced in private than what is conveyed in public interviews. That's a natural consequence of communicating to a population with less expertise than the speaker, IMO.
...and the media picking it up, shouting that thing did absolutely not happen, could never have happened, the debate is over, the science is settled, and anyone who breathes a word in opposition is stupid, dumb, smells bad, and votes for Trump.
You have to acknowledge this is incredibly weak logic. “A thing is possible, therefore it happened.” Is this molecular evidence the Furin Cleavage Site? Cause that was peddled basically as a lie - they occur in nature just fine, it’s also used in research.
I’m unaware of any compelling evidence for the lab leak theory, but I will acknowledge it’s basically impossible to disprove. We don’t know where most diseases arose (or where they came from) - it’s just we mostly don’t care, unlike with COVID.