LDORONO:
This study might still join because you don't know what was said about you when you left. At least anybody within ear-shot now knows that the religion is extreme. I am assuming that the reason you went over to him is because he was a "friend" of sorts who came over your house. Otherwise, why bother? If it were a stranger in the hall I would not bother.
I see JWs in stores and I just have a pleasant expression on my face. I do not go out of my way to greet them but I won't avoid them either. I just act as though I don't recognize them and in some cases it is true because some of these people have aged badly and I wouldn't know them from Adam. So, their shunning routine is wasted on me.