Because that's a word that leads one towards assuming it was a lab leak. RaTG13 and SARS-CoV-2 are different all over their genome. They differ considerably i

Because that's a word that leads one towards assuming it was a lab leak. RaTG13 and SARS-CoV-2 are different all over their genome. They differ considerably in their spike protein because RaTG13 doesn't bind to ACE2 while SARS-CoV-2 and the pangolin coronavirus they reference do bind to ACE2 so they're more similar there. Evolutionary pressures are sufficient to explain the differences, you don't need human gene splicing. And the differences across the genome are decades different. The word "chimera" is being thrown out there to manipulate you into believing their conclusions, they don't really support it at all.