Yes, they are.
But rather than merely gainsay, I'll support that by observing:
a) here in Australia we regularly, consistently, have zero school shootings each year. Can recommend.
b) you are probably misunderstanding the meaning of regular, and conflating it with frequent.
Halley's Comet is regular - at once every ~76 years. But obviously not frequent.
(I'd argue, as per (a), that the USA has too high a frequency of school shootings as well. If your tolerance for slaughtered children is higher than mine you may disagree with that claim.)
Bullying is regular in America. It happens in every school.
Police brutality/abuse is regular in America. It happens in every city with a large enough police force.
Pharmaceutical addiction is regular in America. It happens in every town.
It sounds like instead of just mistakenly using it as a synonym for frequent, you're mistakenly using it to mean something like prevalent or widespread or pervasive.
Either way you're responding to a perfectly valid claim by re-purposing the words used by the parent post and then arguing against that.
No they're not.
> ...that every school holds safety drills for the risk.
They also hold drills for tornado, fire, etc. These aren't regular parts of life either; they are emergencies for which people can prepare for the extremely rare chance it actually happens.
We could debate the utility or practical implementation of active shooter drills compared to fire drills, but just waving your hands saying they are injecting horrors into children's heads is overblown. Most kids just find them a waste of time. Just like fire drills.