You need to understand that the adative view or (adaptionism) is a narrow view taken of evolution that is unrealistic and cannot really be explained. Thats the point it is about just so stories as Gould and Lewetin explained because it is easy to formulate explainations in how a particular trait has provided some fitness benefit and that is why it was selected. This is done at the expense of any other possible cause and that is why it is said to be a narrow and limiting view. This view stems from Neo Darwinism and is still said to be the dominant view in the literature.
Other influences are acknowledged such as under the population genetics view like drift and gene flow as well as recombination and other levels of selection. But it always comes back to as Gould and Lewontin claimed making up so so stories of how natural selection is the ultimate and only realy cause and driver of evolution.
At the end of the day regardless of how variation is reshuffled or lost under the adaptive view it is natural selection that will determine whether those variation will provide a survival and reproductive benefit. All evolutionary change is measured by fitness benefits, how a particular trait gives a fitness benefit to the environment they are in IE the strongest gorilla will mate more compared to the smaller weaker ones and thus his genes are passed on. This is done at the cost of all other possible causes such as the EES forces.
But the other point is that it is not just about NS but also the gene-centric view that all variation is the result of random gene changes which the EES is disputing. Adaptionism and gradualism go hand in hand. This relates back to Neo Darwinism and how evolutionary change needs to be small and gradual as just as Darwin said that if äny complex organ existed which could not have been formed by numerous, successive, slight modification, then his theory would break down".
This view is also still dominant in that eviolutionary change is explained by tiny incrimental changes in especially at the genetic level in the light of genomics. So most explanations are centred around explaining how natural selection can select these tiny modifications as being advantageous for fitness at the exclusion of all other possible influences and causes.