nobody has come up with a serious rebuttal to my terrorist miss-us of GPS scenario
Terrorists can make use of the mobile phone network to detonate IED’s – do we turn it off?
They make use of the satphone network & internet - do we turn it off?
In Cold War times, the Ruskies could (and no doubt did on Oz overflights) make use of the VOR NDB & Omega networks – did we turn them off?
Criminals use cars to commit crimes – do we ban cars?
No. The greater good outweighs those who will attempt to misuse them, and measures are taken to mitigate or prevent the misuse.
In the case of aviation, measures are taken to address GPS & ADS-B outage & degradation, as they are when other navaids are off. Spoofing is addressed in the Airservices system. ‘nuf said on that.
Sleep safely in your bed.