Before you get angry, even though you probably are just because of the title of this post, I do not believe this is true.
This point was mentioned in an article be Menno Henselmans recently, I believe in February. His point is defended by him comparing the muscle hypertrophy obtained by squatting and doing Chin-Ups.
I believe the Deadlift is an incomparable way of developing the Upper Trapezius, the Semi-Membranous muscle, the Semi-Tendinous Muscle, and the Biceps Femoris (Hamstrings).
Besides, it allows you to build muscle in an astonishing way on other parts of the body when you deadlift decent weight and learn to lift explosively, not to mention how tight you have to get in every skeletal muscle to accomplish this lift.
1. What do you believe about this claim of the Deadlift not being a great mass builder? (does somebody actually agree?)
2. What muscles do you think the Deadlift is best for developing [for most lifters]? (Not taking height of the lifter into the matter for practical purposes of this discussion)
*In the mentioned article, Menno does not state the Deadlift is not good for building muscular mass, but he believes there is an enormous difference with the squat and the chin-up.