Before reading this thread, I would have thought it is appropriate to greet a woman on shabbos in the street. But I’ve been convinced otherwise now. I don’t like it.
You’re certainly entitled to your opinion. But a perfunctory “Good Shabbos”, without any intention or desire for further conversation (as evidenced by the fact that in many communities, one will say it to any frum person between the ages of 5 and 100) does not, in my opinion, fall under the category of conversation.
(Several years ago, I asked my Rebbeim the question upon which this entire thread is based, and I was told that it depends on community norms.)