This article confuses me. Why does it make the scientists out to be on opposite sides of the aisle? A giraffe that wins a neck to neck fight is also one that ma

This article confuses me. Why does it make the scientists out to be on opposite sides of the aisle? A giraffe that wins a neck to neck fight is also one that may have better chances of finding food high up a tree when resources are scarce - both can lead to better survival and hence passing of genes. It's not one or the other, it can can be both.