One griefer with a website that offers exploding drone swarms to a given target? 'Most people' isn't everybody, and it only takes one. And the website could be anonymous (bitcoin anyone?)
It's a problem of scale. Say 0.0001% (number pulled from my rear pocket for illustration purposes) of the population want to engage in 'recreational terrorism' or 'orc-work'. If you have a population in the hundreds of thousands or low millions, there just aren't enough of them to have any direct impact on the big picture. But once you get the population high enough, once the absolute number of evil idiots is high enough to cause real systemic damage, even though they are a tiny percentage of the whole.
One tiny group of people hijacked 3 planes, and we're suffering the fallout decades later.
I am almost certain we have laws on the books to deal with that. The point is identifying that before they do anything.
Deal with what? A website that relaunches in the cloud from a different bitcoin account every 20 minutes? Anonymity is great from a personal-freedom point of view, but not so much when assassins start advertising their services out in the open.