My own rov would never pass me by without saying Good Shabbos, good morning, or just hi, if he ran into me when it was not Shabbos. It is simple good manners. The Torah does not asser good manners, and in fact, every aspect of Torah is designed to bring kedusha to the most mundane of things, even saying hello. The Torah is also designed to create Ahavas Yisroel, and not Sinas Chinam. Ignoring someone in the street who has said Good Shabbos to you, whether male or female, breeds sinas chinam, whether or not you agree with my statement (and you would be wrong).