Earlier quoted context omitted.
I think you're wrong about point 4. Could you outline such a plan? As a counter-example: CIA trained operatives with decades of experience and a 20+ person team launching a coordinated attack could only kill 3,000 -- and that was only because of underlying weaknesses in our security policy. The 9/11 attacks were so easy to counter, they didn't even work through one full morning. (By which I mean, 25% of the planes we…
Something like poisoning the water supply, maybe?
Im not saying it's impossible, I'm just saying adding hundreds or thousands of gallons of poison to a distributed system isn't easy nor is it something a few pissed off people can do alone. You're well in to the realm of controlled/watched substances, advanced chemical synthesis, and dozens of people carrying out an attack against hardened targets.