Squatting should not be done on the smith machine. Point blank. When on the smith machine you no longer have to stabilize. It's not realistic. If you want to emphasize your quadriceps you front squat. If you want to emphasize your gluteals you low bar back squat.
As soon as I heard that our shoulders are "designed" to do a lot of work I stopped watching and went to the comments. Hoping that someone had already pointed out that ridiculous remark.
Smith machine is unnecessary for squats. Yes it's safer because it's not a free bar. However, you shouldn't be squatting any weight whatsoever if you cannot perform a bodyweight squat.
Squatting should not be done on the smith machine. Point blank. When on the smith machine you no longer have to stabilize. It's not realistic. If you want to emphasize your quadriceps you front squat. If you want to emphasize your gluteals you low bar back squat.