Although I question his analysis of the necessity of the operation, he makes a very telling point in the last paragraph; our society is not prepared for the realities of modern war.
One thing that is not stated in Boot's article is that there was a tactical change in Japanese defensive doctrine starting with Saipan; defense in depth rather than defending the beachhead as at Tarawa.
Another point not mentioned on this thread yet is the Japanese commander made the tactical decision to allow the Marines to establish beachheads with relatively little resistance (which our forces did not anticipate). Then, once the "easy" landing resulted in a massing of our forces on the beachheads, the enemy opened up on the overcrowded landing areas. (This is based on recollection from readings many years ago.)