You seem to be alluding to the sort of things George Lakoff explores with the idea of http://en.wikipedia.org/wiki/Conceptual_metaphor
Lakoff views political ideology in the US as fundamentally a “family metaphor”, with conservatives espousing a “strict father” model and liberals a “nurturing parent” model. Whether or not that’s the case could use much more research, but the core idea of metaphor as the structure upon which other thought builds is compatible with your appeal to more connotation-aware discourse.
Perhaps a way to address what you’re getting at would be to portray Transhumanism within the family metaphor; children growing up seems particularly fitting to me. What do you think?
An additional benefit of this framing would be to move the locus of attention away from the human-nonhuman issue, as the family metaphor would put connotations firmly within the “human” realm.
It was a fairly naive suggestion with some potential problems, but here’s one way to unpack it using Eliezer’s concept of Future Shock Levels (http://www.sl4.org/shocklevels.html) as a guide:
The parents are “old-style” humans.
For those with a shock level that is quite low, they would adopt the role of the parents. Although retaining perhaps disdain for new fads, etc., it’s an understood social situation. This reframes what might be construed as unpleasant societal upheaval into a “standard” form of societal upheaval that occurs every generation.
For skeptical individuals who are at a sufficient shock level, the maturing children would be appropriate, redirecting the human vs nonhuman connotation into a cultural phenomenon where change and distinction over time are accepted or at least tolerated.
As mentioned in my comment above, although Lakoff is quite careful that his theoretical underpinning are solid (falsifiable, etc. etc.) the particular question of whether the family metaphor really is the dominant one in American political culture is not nearly as reliable.