Ok, let me rephrase it: "It is very comparable to the flu if you look at the time when Columbus introduced illnesses in the americas that would later benefit eurpean settlers - and so unknowingly introduced biological warfare to the americas".
Unknowing introduction of a virus being 'biological warfare' would imply that people flying out of Wuhan in late 2019 were actually engaging in biological warfare. That's a stretch. There's no world, no matter how well intentioned Columbus may have been in an alternate universe, where disease doesn't devastate immunologically naive populations.
Unwittingly spreading disease is simply not biological warfare. There is no such thing as “unknowingly” waging it. That is just a pandemic.