I'll go: because while the parent comment is (loosely, tangentially) based in fact, it's an enormous leap to go from the kind of differences we're talking about

I'll go: because while the parent comment is (loosely, tangentially) based in fact, it's an enormous leap to go from the kind of differences we're talking about with SARS-CoV2 engineering, and the differences of type required to aerosolize a filiovirus. Is it "possible"? Yes, theoretically. But it's not at all trivial, and far down my worry list. It's bit like worrying that sharks are going to evolve wings and start flying around eating people.