Technical quality or character, technicality; the extent to which a people, culture, etc., possesses technical skills or technology.

http://www.oed.com.ezp.slu.edu/view/Entry/271683?redirectedFrom=technicity#eid

Siegert seems to be saying that the focus on "the distinction between human and non-human" has been taken too far, that it's a matter of technicality that serves little to no purpose for all its specificity.