Some human groups have used human waste as a fertilizer, in the absence of other, better sources. Human waste isn't particularly massive or nutritious, and would be a lower tier choice.

Also, pastoralism is often related to patricarchy and sharper division of labor, so just because all we see are the male giants doing work, that doesn't make them aberrant. Just more visible. Its also not that different from possible human social structure in the early hominids, who weren't meat eaters.