So in one sense you're right, we can only debate the likelihood of finding facts to support the theory of lab leak vs natural origin right now. The aim of this paper is to encourage that debate rather than try to silence it, the way the natural origin proponents seem to want to do.
Now, in this case, the fact is hidden from us. SARS-CoV-2 had a natural origin or it didn't, but we don't have enough evidence to decide that question either way. In the absence of evidence, people are using prejudice to decide what is true, and trying to persuade others to adopt their prejudices. That is utter folly.
What we should do is give up on trying to establish the facts unless and until new evidence emerges. Instead, let's admit that lab leaks are possible, and regardless of whether it happened in this case, it should cause us to reexamine our assessment of the risks inherent to this type of virology. We have a demonstration of how bad we are at containing epidemics, and how damaging even a relatively benign virus is. We don't know what a more deadly virus would do, but we can safely assume it would be very bad.
Ok, I grant that I was a little harsh on the authors of this paper; they're really only saying that the lab leak is plausible, and we should examine it seriously. Fine. But I still think it's a red herring. Even if we could find patient zero and nail down the animal that infected him to conclusively prove a natural origin, we should still revisit our thinking on whether and how to conduct research with viruses. That we're a long way from that sort of conclusion makes it all the more important.
Whether COVID came from a lab or not is only of tangential importance. If you have a system in place, it will get breached eventually. Forever and always. It's China. Nobody else is responsible for China.
What is VASTLY more significant, and where most of the debate is centered, is how we responded to the fact that a deadly virus was spreading. The terms "Wuhan-flu," "kung-flu" and "China virus" were direct attempts by political leaders to deflect the responsibility for their lack of action and failure to mitigate the affects of the virus.
Hell, it's a lesson even a child should know: you are not always responsible for the situation you're in whether that's a kid picking on you or COVID, but you are fully responsible for your reaction. My son's favorite word right now is "well...." because as very bright 8 year old, he wants to discuss his reasoning process with me to justify why he acted the way he did. And mine is "well, nothing..." because most of the time when we have these incidents, his reaction is out of step with how we've taught him to behave in the situation.
The political arm of the Trump administration was FULL of "well..." instead of addressing the issue, and the political polarization of the US has allowed a big percentage of the population to justify their own responses to mitigation efforts in the same manner. Because most adults have gotten there by reaching a certain age, not by reaching maturity.
I remember watching in horror as the US was shutting down its borders because the virus had spread to Europe, but people were packed into our major international airports like sardines and remained there for hours. It was and is incredibly stupid and irresponsible.
The problem is that prejudice one way leads to never solving the mystery at all, and prejudice the other way leads to having a snowballs chance in hell of solving it.
One party in this saga is actively covering up all evidence. So unless we hunt down what exists now (if anything still does) we’ll never have the answer.
I do agree that the answer doesn’t particularly matter though. It’s best to act as if it were a lab leak, and natural infection both, and change procedure based on that.