a) we're not allowed to put phones in it due to the lithium content.
b) I doubt in the moment of anger at the piece of shit, taking it home and politely disposing of it would have the same mental satisfaction as smashing the bastard thing to bits on the motorway.
Irresponsible or not, humans aren't perfect unless they make condescending remarks on the internet.
It's easy to criticize from the couch, but throwing a phone from a car window is VERY irresponsible. I doubt that in the moment of anger she looked first to see if there was someone else on the road.
Being hit by a phone while riding a motorbike doesn't seem fun.
Throwing anything from a moving vehicle should lead to instant driving license annihilation. You make light of it but people get killed that way.
If you can't control your impulses to throw stuff out of your car in fits of rage then you don't belong on the road. It's a shared resource, and using it is conditional on your behaviour.