But............ the fact remains that there are bows that will shoot a lighter arrow with more KE than a heavier arrow under the exact some shooting conditions; i.e. same bow, same draw weight, same draw length...only the arrow changed.
I think you mean they will shoot a heavier one with more KE than they will a lighter one which I agree with totally except there is a point at which that no longer becomes true. There is a point at which as you go up in weight (granted not at normal hunting weights) that the bow will become less efficient when the weight gets up high enough.