I was replying to this:

There's a persistent myth that Facebook Group is the same as Google+ Circles.

I don't think that myth exists at all - I've never seen anyone say it until you brought it up. The parent post used the word "groups", but didn't specify they meant "grouping people" as opposed to the Facebook group functionality.

Further, I reiterate: Google+ does not work like Unix groups

Again - no one is claiming that. I used Unix groups as an analogy (because they let you group people together).