My impression:
S&C coaches.....lifting in general (bodybuilders, powerlifters, etc).......is a dik swinging contest to show who's the best and why "my" techniques work best.
During my time, i trained with football players, bodybuilders, powerlifters, weekend warriors, personal trainers, etc (some natural, some on roids) and i could tell you stories upon stories on the "proper ways" of doing things, many of which conflict.
I had a bodybuilder show me horrible technique on leg press, to get the extra stretch......putting excess curvature and pressure on the lower spine.
I had a powerlifter show me horrible technique on a bench bc all they cared about is weight, not form (their bench shirt forces them into better form during competition).
And the football players? Some chose to workout with us on their off days bc they weren't getting enough gains from their regular S&C routines.
Every person and every situation is different.