I'd say that the "Proximal Origins" paper makes a very weak case especially given what we now know. The essential argument is that it's more likely that the RB

I'd say that the "Proximal Origins" paper makes a very weak case especially given what we now know. The essential argument is that it's more likely that the RBD came from a lineage that includes the Pangolin-CoV than that it was designed by a human. That does seem reasonable. They suggest that the virus was the result of a recombination event. However, that recombination could have occurred artificially at the WIV. The WIV and Shi Zhengli specifically have recently published papers about performing precisely this type of work on SARS like coronaviruses. Now the closest known viruses to SARS-CoV-2 are RaTG13 and Pangolin-CoV. Pangolin-CoV is a very close match in the spike protein, and RaTG13 is a very close match on the rest of the virus. RaTG13 and Pangolin-CoV were both discovered by WIV but their sequences sat unpublished until after the pandemic started. The grafting of the spike protein onto a "backbone" of another SARS like coronavirus is specifically something Shi Zhengli has been involved with and published with Ralph Baric in 2015. Furthermore, the spike of SARS-CoV-2 is better adapted to humans than to any other species, and it's better adapted to humans than any other published coronavirus. This doesn't make sense unless the virus spent some time evolving in humans or in human cells. Interestingly, passaging SARS like coronaviruses in human airway cell cultures is also something that has been done in recent years. Ralph Baric's lab specifically has published work on this. The only real other possibility is that SARS-CoV-2 somehow spent many months circulating in human populations undetected while it adapted to human ACE2. There has been no evidence published that this occurred. Finally, it is quite a coincidence that the lab where both Pangolin-CoV and RaTG13 were discovered is in the same city as where the outbreak started. Yes, both of those viruses were discovered in China, but Pangolin-CoV was discovered about 1000km from Wuhan, and RaTG13 was discovered about 1500km from Wuhan.