Too much imagination with no real think-through:
*Setting ALL traffic lights EVERYWHERE continuously to GREEN - Is this fear mongering? EVERYWHERE? really? 99% of traffic lights are not connected to any grid. Maybe they have local transponders that Ambulances can request green, but it would be negligent to allow a situation that could bypass the interlocks that prevent all-ways green. There is only so much that software hacking can defeat. The professional engineer that would ever allow that situation would be put in prison.
*ATM's across the nation spewing out wads of cash (riot ensues) - ATMs and banking in general do not rely on the internet for core operations. You may find some stupid private ATMs to be vulnerable, but that is their problem. Web banking for customer-access of course is an exposure, but a genuine effort is applied to closing holes in those systems.
*Cutting electricity at night (riot ensues) - Have you ever experienced a blackout? I have. People survive. We are not animals. But, this one is interesting because there are documented cases where power plants have some malware present. However, I am slightly skeptical that PCs would control machinery in a way that a hacker could exploit directly. It would require a program that could specifically interfere with the development and deployment of code into PLCs and other real-time systems that causes damage. Not impossible, but way up there in the 1% of possible things that could happen. Most likely any corruption of information systems could be over-ridden by engineers or resolved by backup systems. There is a much more likely chance of physical sabotage (actually has happened in US.)
This is still the most credible threat, but the fact that it isn't an everyday occurrence like identity theft says that there is either insufficient motive, or other mitigating factors. If it was as easy as some news reports claim, then bored hackers everywhere would be doing it. To the original point, the solution isn't retaliatory strikes on other nations, it is regulatory fines on the idiots who don't understand how or why to firewall critical infrastructure.
*Resetting GPS coordinates ala Die Hard (2 I think) so sea level is revised - I'll leave that to a person who actually understands how that system works. My Spidy-sense says that is just Hollywood.
*DDOS facebook (riot ensues) - LOL probably true.
*Resetting/rebooting medical hardware - Possible, I'll blame the PHBs who allowed that equipment to be connected to public networks. Otherwise, they will continue normally if on private/inaccessible networks.
*Disabling cooling systems at nuclear reactors - Not really substantiated. Explain why the NRC allows the control systems to be web-enabled,
*Robovacuums commanded to "suck up the cat" - You got me there. I don't own one.
*Trains accelerated to maximum speed, brakes disabled - Same reasons as traffic lights and nuclear reactors.
Further examples:
*Hackers lift info from my computer and blackmail me. Why? because free market doesn't understand how to enforce better quality in OS's, and consumers have no power over this.
*My credit card numbers compromised for the 10th time. Why? because free market doesn't care and consumers are not well enough educated/powerless to demand chip-and-pin systems.
*Website goes down and I can't pay my bills. I pay my bills tomorrow when situation resolved.
*Movie studio leaks/hacked/whatever latest movie. Kinda their problem to instill loyalty on insiders and have secure systems.
*Some DIY'er puts his whole home automation online and hackers have fun spying on bedroom / unlocking front door / ordering endless supply of water filter supplies. - Sorry dude, you should have known.
*Car entertainment systems blasts Pron at 100 dB while children in car. - probably will happen soon. I don't trust all car companies to put quality and security first.