I take you'd regard it as offensive to slaves to describe their condition as 'subhuman" too?

It is.

Anybody can be reduced to a subhuman condition by an oppressor, and the first step to doing something about it is to recognize what's been done to you. Like, when did you vote for a society where all you can afford to eat is lethal greasy filth?

I can just see some of the people who try to depoliticize this issue as advocating "slave acceptance" 150 years ago.