Division of Labor and Opposable Thumb

Marx-Engels recognize the sexual act as constituting both the original Division of Labor, and the nucleus of exploitative relations.  Now, regardless of whether or not each of those attributions is accurate, another equally primitive Division of Labor can be found in the human hand, specifically in the distinction between the thumb and the fingers.  More precisely, that distinction is generally characterized as opposition, i. e. the thumb is generally classified as 'opposable'.  But, unlike other oppositions in Marxist Dialectics, this one is not at all antagonistic, nor is it exploitative.  Rather, it is the source of the capacity that makes most of human labor even possible--the grip, without which most tools would not even exist.  So, the exploitative antagonism that they try to attribute to Division of Labor, is not, as they try to establish, inherent in it.