> has not been found in any other beta-coronavirus.
That does not mean it doesn't exist, just that we haven't found it.
We didn't know of any other sarbecoviruses that had furin cleavage sites, then we found them in bats in Thailand, then the goalposts moved to how this paricular furin cleavage site is weird.
Once a decade passes and we find animals with beta-coronviruses which have the same kinds of furin cleavage sites, I'm sure the goalposts will move again.
Granting that, or even granting that the virus wasn't modified in the WIV (merely collected and then accidentally released) at all: we need to find the animal population that it supposedly jumped into people from -- and 18 months later we haven't.
That does not mean it doesn't exist, just that we haven't found it.
We didn't know of any other sarbecoviruses that had furin cleavage sites, then we found them in bats in Thailand, then the goalposts moved to how this paricular furin cleavage site is weird.
Once a decade passes and we find animals with beta-coronviruses which have the same kinds of furin cleavage sites, I'm sure the goalposts will move again.