https://www.biospace.com/article/1nih-awards-ecohealth-allia...
- China intentionally manufactured the virus and released it (Proven false, virus wasn't engineered)
- China accidentally released the virus while collecting it (Possible, but unlikely given the virus has early evidence away from both collection point and Wuhan Lab)
- China has too many wet markets that allowed the virus to mutate enough for human jump (Current consensus working theory, but also unproven as intermediary animal has not been identified)
But all of these list China as the responsible party, so if you want to call it out as not Xenophobia or Anti-China sentiment then you'd have to show evidence the reporting showed "Joint Sino-American research lab causes..." kind of headlines. Otherwise, you point strengthens that this has at least an under current of anti-china sentiment, as the reporting has not mentioned US involvement at all.
WHO of course have a lot to answer for with regards to ignoring Taiwan because if BS geopolitics when they had the most reliable/believable/compelling evidence of the nature of SARS-Cov2
The most common lab leak hypothesis I've seen is that it was engineered during gain-of-function research and then accidentally leaked.
The fallacy is just that the only reason someone would engineer a virus would be to weaponize it. Gain-of-function research is regularly done to study and combat viruses. So just because it was engineered doesn't imply it was intentionally released.
This was the significance of the pangolins, which were initially proposed to be the proximal animal host. But while it initially seemed that multiple infected pangolins from different sources had been found, it later turned out multiple seemingly independent papers had been written based on the same pangolins[2]. This means it's much more likely that something else infected those pangolins, in the same way e.g. that some housecats have been infected by their owners.
Nature has added an editor's note[3] to one of the pangolin papers, and even Daszak and the Chinese have pretty much abandoned the pangolins. So for now, there's no known animal host for SARS-CoV-2, unlike for the original SARS-CoV (palm civets) or MERS-CoV-2 (camels). Perhaps the animal reservoir just hasn't been found yet; but it's also possible that animal reservoir doesn't exist, because SARS-CoV-2 originated from serial passaging in a WIV lab. That's just natural evolution under unusually fast selective pressure, so any arguments that SARS-CoV-2 shows no evidence of genetic engineering are inapplicable to that theory.
1. https://wwwnc.cdc.gov/eid/article/26/12/20-2308_article
2. https://www.biorxiv.org/content/10.1101/2020.07.07.184374v2
1. Direct artificial manipulation of a virus's genetic sequence.
2. Laboratory culture and passaging of a virus, allowing evolution due to natural mutations to proceed under artificial selective constraints.
No one serious is focusing on (1). The people bringing it up most often are either uneducated cranks, or zoonotic origin proponents using it as a strawman to refute.
The serious concern is that SARS-CoV-2 originated due to (2). In that case, since it's a natural evolutionary process, there would be no indication in the virus's genetic sequence of human tampering, because no direct human tampering occurred. The only evidence would be the absence of any animal reservoir of the virus. Perhaps that will eventually be found; but so far--unlike for SARS-CoV or MERS-CoV--it hasn't been.
As I note elsewhere in this thread, the discovery of a proximal animal host would convince me that the virus is probably of natural origin. Is there any evidence short of a direct admission from the people responsible that would convince you it might have escaped from a lab?