I think that the problem is that it is difficult to prove or disprove and they base the probability on the fact that if you wanted to produce a virus with these characteristics you could do it more efficiently, but I think they don’t rule it from this statement:
” Although the evidence shows that SARS-CoV-2 is not a purposefully manipulated virus, it is currently impossible to prove or disprove the other theories of its origin described here. “
I believe that the most susceptible animal models for infectivity are cats and ferrets.