If you draw a straight line on the map between Trail Camp and Trail Crest, it is only 0.7 mile. And the elevation change is 1600'
But your entire Whitney hike covers 6000' of gain, and the stretch after Trail Camp comes after you have already covered 4000' of elevation and 6 miles. That slope above Trail Camp, by itself, isn't a big problem. However the elevation AND the energy required just to get to the base makes it a monumental physical achievement.