"When an agency comes out and says they're leaning this way but with 'low confidence?' I mean, how do you interpret that?" Michael Osterholm, director of the University of Minnesota's Center for Infectious Disease Research and Policy, told Axios. "The question is: 'Why did you even put it out there?'" he said.
Low confidence generally means questionable or implausible information was used, the information is too fragmented or poorly corroborated to make solid analytic inferences, or significant concerns or problems with sources existed.
In answer to Osterholm's question:
The Department of Energy "put it out there" because someone with influence over the US Department of Energy wanted to keep the lab leak hypothesis alive.
Note that I refer to it as a "hypothesis" rather than a "theory."
A theory is testable and falsifiable.
The lab leak hypothesis is not a theory because it's not testable (the Chinese regime isn't going to suddenly open up all its facilities and records) and because it's not falsifiable (even if the Chinese regime disappeared today and US inspectors went in with all the access they wanted and dispositively concluded that there was no lab leak, those who want to believe there was a lab leak will continue to believe there was a lab leak).
Absent testability and falsifiability, all those who really care about getting it right have to go on is Occam's Razor: "When presented with competing hypotheses about the same prediction, one should prefer the one that requires fewest assumptions."
It takes a number of assumptions about subjects of research, techniques of research, and lab security practices to get to "lab leak."
The only assumption it requires to get to "zoonosis" is the assumption that the SARS-CoV-2 has the same origins, and infected humans by the same means, as most infectious diseases.
Does that mean the lab leak hypothesis is false? No. It just means that in the absence of evidence for it, there's no particular reason to fixate on it. And a "low confidence" "assessment" from a state apparatus with at most an extremely tangential role in such "assessments" doesn't change that calculation.