That letter may seem perfectly tepid and reasonable out of context, but Andersen has publicly criticized it:

> But, “the letter suggests a false equivalence between the lab escape and natural origin scenarios,” he said. “To this day, no credible evidence has been presented to support the lab leak hypothesis, which remains grounded in speculation.”

https://www.nytimes.com/2021/05/13/science/virus-origins-lab...

Dr. Shi too (though she obviously can't deviate from the CCP's position without putting herself in physical danger):

> The chief scientist for emerging disease at the Wuhan Institute of Virology, Shi Zhengli, said in an email that the letter’s suspicions were misplaced and would damage the world’s ability to respond to pandemics. “It’s definitely not acceptable,” Shi said of the group’s call to see her lab’s records. "Who can provide an evidence that does not exist?"

https://www.technologyreview.com/2021/05/13/1024866/investig...

The controversy isn't "people who don't think lab origin merits further investigation" vs. "people who don't think natural origin merits further investigation". It's between people who think lab origin is so unlikely that no further investigation of that possibility is necessary (like Andersen and Rasmussen, along with the CCP), vs. people who think both possibilities are sufficiently likely that further investigation of both is required (like Chan, Bloom, Baric, Tedros, Redfield, etc.), as expressed in that letter. I'm obviously with the latter group. For example, I believe we should push China to release more records from the WIV, but I also believe we should keep sampling animals looking for a natural intermediate host. If you study the evidence yourself then I believe you will agree.

As I noted above, as best I can tell the FCS is mostly a distraction--interesting, but not determinative either way. (Although again, a Nobel prize winner seems to disagree with me.) I'm much more convinced by the origin city and distinctive nature of the WIV's work sampling novel viruses from nature, by the lack of an intermediate host, by China's removal of access to the WIV's database of viral genomes in September 2019, by their blocking reporters from the mine where RaTG13 was discovered, and other such non-genomic evidence. This evidence is also much easier to judge without advanced scientific background.

ETA: And for emphasis, "no genetic engineering" also doesn't imply "no lab origin". For example, it's entirely possible that SARS-CoV-2 is a naturally-evolved virus accidentally released by the WIV. They routinely sampled remote, virus-rich bat caves that no other human would enter, with nothing more than a surgical mask and nitrile gloves. They could easily have brought a virus back to Wuhan and released it before even sequencing it, whether in a lab accident there or in a researcher who became infected in the field. I urge you to research and understand this yourself, instead of deferring to strawmen set up by virologists with little distinction beyond their Twitter following.

ETA2: And note that Andersen and Rasmussen both now claim to support further investigation, but prior to the Science letter they did not. They also seem to support it only in the abstract, and to shout down any calls for specific actions (e.g., pushing China to release the WIV's virus database). This is a long story; please try to understand it in detail, and don't take any isolated claim from any side at face value.