I think it's definitely viruses. Doc Shelly is wrong.

Quite possibly. But very uncertain. It could be viruses… it could be something else. Read basics again.

You were right, however, about it not being bacterial spores. If there were bacterial spores, it would have still been infectious! Doc #2 got it wrong. You have to heat it to 100 degrees Celsius to kill bacterial spores, not 90.