memes

I think the more important overlap is in the brain itself. We have known that regions of cortex that register genital stimulation are adjacent to/overlap with the area hat registers foot stimulation since Penfield did the first mapping of cortex in the 1930s.

In answer to "that's true for perception, but why the excitement for looking" lays in that the homuncular representation is not a simple one. We know that there are multiple homuncululi tied to different types of perception, and there is more modern work that ties the planning and goal systems to the functional centres around key points of the homonculi. The physical closeness of the two is possibly responsible for the mingling of the two representations. Back in the day there was even a mechanism for it - "ephaptic excitation" - where axons running in a bundle could activate neighbouring fibres through changing the ionic composition of the fluid around them.