During my one and only visit to Yosemite, I recall hiking up Four Mile Trail to Glacier Point and being almost offended by the scores of people who exerted no effort taking the bus up from the valley (I have since softened my attitude on the subject). Granted this particular trail is immediately adjacent to the valley, but I still didn't think that these people had nobly gained the summit. The same might go for Pikes Peak in Colorado - with either a car or train ride to the top - where otherwise very few people would ever go.
But where does it stop? The great paradox of the National Park Service has always been to figure out how to allow people in without destroying the resource, but with your rationale, taken to its logical conclusion, cars and busses would be removed from the roads, and then the road itself would have to be removed, then pedestrians would be barred. Recall further that the first documented siting of the Yosemite Valley by white explorers in the 1830s were from the rim walls; the travelers simply couldn't negotiate their way down to the valley. Should we have just left it there, never opening it up to visitors who were not physically capable of repelling down rock walls or hiking through native forest and undergrowth? Indeed, I would assume that your visits to Yosemite were by way of automobile on a paved road (which is akin to a golf cart on a path), not on a horse like the "purists" of days gone by, or the walkers before them. In many ways, then, we are all "cartballers."