On the other hand, I did some primary school in New Zealand and we had what I would now call a lock-down for the same reason, where school shootings really aren't a thing. I think schools ought to plan for that kind of thing for safety. I think the kind of first aid they teach you in active shooter training if you happen to take them as an adult (I did because I had a buddy trying to start a business after leaving the military doing it) is actually also really good first aid for anyone who's doing extreme sports, or going in the wilderness, or working around heavy machinery, etc.
I don't think any of that means that people shooting up schools is accepted as normal.
edit: Now that I've read TFA, I'll also add that I've worked in the US my entire adult life and I've never had active shooter training that was mandated at work, or heard of anyone I know having that.