I just read that article, and the guy is right. I've already given extensive thought to this.
You can't just pick a few "Alpha Male" teachers, and put them through a training course or a weapons qual - and I do mean "Alpha Female", too. Gender doesn't matter.
You need to REPLACE a portion of your teaching force, completely. What you need to replace them with is Combat Veterans. I can tell you right now, I know more about "teaching" than some fresh-out-of-college Master's-of-Education Degree-having snot-nose college motherfucker - that has ALL the credentials of being able to teach, with NO PRACTICAL EXPERIENCE.
Militarily, you, as a leader, TRAIN your Soldiers all the time. Training is teaching. However, you're not training some schoolbook verbatim text bullshiit. More often than not, you're training some high-risk shiit. Not anybody in the civilian world can just "decide" that they want to be a firearms instructor - you have to go to specialized training, gain certifications, study under someone before you can be a course instructor, or lead instructor.
Militarily, you'll see 20-year olds and up as weapons trainers - and that's based on their own experience. Maybe even younger. Proficiency and rank drives that train - and exhibited proficiency gets you promoted. Hell, for 5 years, I trained SOF Static Line Jumpmaster - Jumpmaster School - and the last 2 years I trained it, I was the Course NCIOC - I RAN that fucker, from soup to nuts. You're training people in a specific skillset that will put other Soldiers lives directly in their hands, and if they fuk it up, those Soldiers will die. Literally. In a jump unit, that's a daily operation. In a leg unit, that's some high risk shiit that would have some Bn Commanders freaking out over the Risk Assessment, trying to find a way to not approve it for the event.
You can't just "pick from the staff" at a school, and determine who is gonna be the "teacher/protector with gun." You must REPLACE a portion of your training staff with Combat Vets that can, and have, already done this job. For real. When it counted, on the battlefield, in the name of "Preserving Democracy" and protecting this nation.
I'm off my soapbox. Fuk it.
Tom-Ass out.