Earlier quoted context omitted.
Some of the ones which are done during the school day, involving students, sound horrific: Active-Shooter Drills Are Tragically Misguided, https://www.theatlantic.com/magazine/archive/2019/03/active-...
This feels like a weird thing to say but exposing students (or anyone) to this seems like a really bad idea. By letting them experience that kind of terror, I feel it may give anyone with sociopathic tendencies 'ideas' and may influence them to seek that kind of control over others. We're all just the sum of our experiences and giving young impressionable kids terrifying experiences in the pursuit of protecting them…
Sociopathic kids will use the events and memories from the drills as triggers to intimidate and remind their peers of the threat - or as you say, even further as inspiration for actual attacks.
And I'd be willing to bet there are some unusual psychological characteristics of the folks who perform these drills and arrange them - does a normal-minded person really want to teach others what it's like to live in threat of imminent death?
All of this time and money should go to reducing the possibility of shootings occurring in the first place, and reducing the cycles of hurt which lead to them, rather than re-enacting and normalizing them.