I'd wager the law is written more as a way to be able to charge people who the authorities are concerned about but haven't provably done anything yet. Not that

I'd wager the law is written more as a way to be able to charge people who the authorities are concerned about but haven't provably done anything yet. Not that that's much better but that's the slightly more reasonable application of the law. There's been several times where the people who've gone on to do attacks were known to whatever the national security services were but hadn't been caught actually planning the thing. It's the kind of law that'd be great in a world where government is and could be guaranteed to always be run by angels and saints but is absolutely untenable in the real world.