It’s hard to stop a well trained person who just snaps one day.
That’s not what we’re seeing.
I haven’t seen anything that says the El Paso guy was in the service.
He was practicing.
He even mentioned how hot the barrel became after putting 100 rounds through it.
This isn’t a guy who just snapped one day.
If he were as the manifesto claims then there would be hang-out buddies from the gun range and/or other venues.