[Drolefille]

cheerfulgreek you're right, it is an inherent way that humans look at the world. Go back in time: You toss a stranger into a "kin or not-kin" category. Later in our development we'd toss a stranger into Foe, Uncertain, or Friend.
Food is good vs. bad. Then it's good-tastes good, good-tastes bad, etc. Now it's high in carbs, low-fat, delicious but will set my diet back for a week, etc.

We like to put things into boxes and smack labels on them so we don't have to consciously think about the qualities of that person, food, thing, anymore.

I know I do it myself, I do try to be aware of it and catch myself if it's inappropriate.