After 15 years in Cyber i can say it is really easy to cause mass casualties. OT is criminally indefended and can have insane impacts. There is just no benefit for anyone to do such things.
Its not a matter of people not being able to do it. So having more means to do it, i dont think will change that.
People are filled with negativity each day and fear someone wants to destroy all humans. The vast majority of people, even those who make mistakes and do bad things, do not actively want to harm.
its painfuly obvious that the problem is people experiencing massive amounts of fear, not actually those fears being real or not.
What does fear do, and why must we experience it then?
Because fear makes people look externally for security. And security pays $$$$. This is a big reason for large societies to come into existence. To get rid of primal fears.
It is a marketing mechanism older than time itself -_- to get people to hand over their riches based on some probabilities of perceived risk.. usually very low ones. Since they are usually low probabilities, rational people would mostly take the risk, so they get overstated to emotionally trigger people.