The refusal to wear masks, which is a trivial form of "opsec" against infection, shows what happens.
It's boring, uncomfortable, unsexy, protects you against an outcome you think is low probability, and you don't find out if you're doing it right - only if you've done it wrong, by which time it's too late.
Besides, since these terrorists had no concrete grievance, only internet radicalization, they ended up doing more cosplay than effectiveness.
A funny side note with that... there was a recent theft of $3000 worth of Crest Whitestrips in my city that got some news attention. It was 3x 40-50 year old white folks that did the theft; the woman distracted the clerk while the two men loaded up. All caught on camera. AND THEY DIDN’T WEAR MASKS.
They had every opportunity to cover up their faces in a completely socially acceptable way and didn’t. C’mon.
It's boring, uncomfortable, unsexy, protects you against an outcome you think is low probability, and you don't find out if you're doing it right - only if you've done it wrong, by which time it's too late.
Besides, since these terrorists had no concrete grievance, only internet radicalization, they ended up doing more cosplay than effectiveness.