I know what you mean - honestly I do - I even fell for that IronMan 'Positions of Flexion/ROM' shit in the '90s (oh brother)
But quads have 4 heads, so surely different exercises or positions might hit different bits, no..?
(BTW I only front squat nowadays so don't care either way
)
Taffin ducks for cover 
“Supposedly” that is where Yates and Mentzer disagreed.
Mentzer apparently thought that a muscle could be hit fully by a basic movement if the resistance was sufficient enough to stress the muscle beyond its previous limits. Also, if the weight was moved through a full range of motion, and there was sufficient recovery time afterwards... you could get maximum results.
Yates obviously believed that the different areas of a muscle group needed various exercises for max results, especially the back muscles.
But as we all know, some of the champion bodybuilders trained much differently than they had preached.