I thought it would only slightly tweak the speeds so it would ruin the result. It didn't destroy them.

If the software physically destroys the hardware that is running it, I'd say that's fairly violent. Stuxnet, the virus it's being compared to, destroyed the centrifuges it infected. Sort of the issue with the "more violent" explanation so far is that Iran isn't saying how bad the damage is, and it sounds like this new virus might be hitting critical infrastructure like power systems, but no one will say anything beyond "systems are being attacked".

Turning off or modifying automated systems in any large device - buses, cars, airplanes, centrifuges, stadium roofs - would have potential for massive violence/destruction.

tesla.brakes = false

while(true) tesla.speed++

Medical technology: pacemakers, drug infusion pumps, digital x-ray and MRI systems ("nope, no lesions on your lungs").

Industrial materials fab: change raw materials in critical alloy mixtures; mess with annealing time/temperature recipes; dial down forces in component proof tests ("oops! Why did that turbine rotor blade separate?").

Lots of opportunities for malware to be nasty outside of weapons systems.