Anthropocene and Ecosystem

The current debate among geologists--whether or not the Earth has entered an Anthropocene Epoch, and, if so, since when, is methodologically unsound in at least two respects, even granted that there are precise criteria for determining that Humankind has 'significantly' affected the terrestrial ecosystem.  First, whether the proximate cause is the 18th Century Industrial Revolution, with its increase of carbon dioxide, or the Agricultural Revolution of circa 10,000 BC, with its deforestation, or even more primitive hunting, any accurate gauge of impact on the ecosystem requires a base case of zero impact, which, since it entails both the presence of a human measurer, and the non-presence of humans, is impossible.  Furthermore, all the accepted indicators of influence are destructive, which arbitrarily preempts the possibility that Humankind has functioned constructively in some respect within the ecosystem.  Obviously, the debate is specifically occasioned by Climate Change, but it also presupposes the theological premise that Humankind is an alien intruder into the ecosystem, and, therefore, a malevolent one.  Surely, ecologically damaging Human activity requires correction.  But an inadequately grounded declaration about geological epochs is not an effective means to that end.