Interesting question. It has to do with the nature of the ROM in the exercise. In a squat, the ROM of the motion is defined by the hips and knees. If by the ROM of a shrug you mean the elevation of the AC joint, your criterion is quite different. This is why shrugs are not considered a major exercise. They are useful for the deadlift for a couple of reasons.
1. The short ROM eventually becomes so short that it's actually isometric as the weight gets up above the deadlift 1RM. Since the role of the traps in the deadlift is isometric anyway, this is fine because it overloads the trap function.
2. Since the shrug starts above the knees to permit the heavier weight, it acts as an overload for the hip extensors and the erectors too.
Many record deadlifts have been performed without this overload, so heavy shrugs are optional. But they do make your traps grow, and the overload is useful for the reduction in perceived "heaviness" during a big pull. A 405 shrug is not "heavy," and 225 is not a shrug weight for a male lifter.
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"Is the big bad government "oppressing" you -- Wah, wah, stomp, stomp?" Depends on whose government is in power, I suppose.