This is an argument from incredulity.
This one was, yeah, this is a virology institute, we study corona viruses, we were hiring for corona virus experts, we do GoF work, but trust us, just because it first appeared blocks from our facility, it did not come from us. Also, don't believe our former virologists who skipped town.
I mean sure, anything’s possible, but we have only circumstantial evidence right now and this observation isn’t a smoking gun, but it ain’t worth nothing.
SARS after all was found in civets, and then later several other species as well despite originating in bats.
We can’t rule it out, ie. we only have evidence right now to try to make a determination based on the preponderance of evidence, not beyond a reasonable doubt. The story that is emerging is that we may never be able to prove something beyond a reasonable doubt because the debate was quashed for a year by political concerns, institutional biases, and motivated reasoning.