Especially because how hard it is to deal with the consequences. If a town's water supply is polluted you can shut it down and deliver water by truck until the situation is resolved. The consequences might be serious, but it would be a one-off event with limited consequences. Similarly, shutting down all freezers in a cyberattack would suck, but the consequences are limited in time

A new bioweapon let lose would be incredibly difficult to contain, and could potentially become something we have to contend with forever