A school shooter isn’t trying to say “shut down all schools”.

But a terrorist flying a plane into one of the most important symbols of your most important city is certainly trying to send your society a message.

Same with this killing

Think about how you would feel if some guys beat you and your friends up in a bar fight, vs someone individually stalking you and beating you up outside your own house. You got beaten up in both cases, but the bar fight beating will unlikely make you feel as vulnerable and scared to leave the house as being stalked and targeted individually