Its a spurious criticism. There were no open flanks, to attack. But more important is the army that formed the AEF had not existed a year earlier. 90% of the officers and NCO had been civilians in April 1917. Those in the state militia had not been any better off & there was no Army Reserve as we know it. six or ten months was not time enough to learn sophisticated tactics, even the Germans had trouble making the Stosstruppen units and infiltration tactics work correctly. The AEF did what it could. In the Mont Blanc attack the corps commander could have gone for the high ground as per the text book. Instead he avoided the strongest defense in front of it and made the main attack to the flanks, technically a frontal attack, but the flank attacks forced the defenders off Mont Blanc without focusing on the main defense.