I always protested when someone called me Rabbi. Personally I thought that calling me Rabbi disrespected the title. Without fighting what is probably the established minhag, I couldn't let people use it on me.
After I actually got semicha, I let it be. (Can't disrespect RYB who signed off on it.) So anyone who it bothers to be called Rabbi should simply go get a semicha... Nidda is the easiest, I think.
Agav, that anectode about HaRav Shraga Feivel on the first page of the discussion is inaccurate. Rav Shraga Feivel did get semicha. He just didn't identify as Rabbi, regardless.
There is one story brought that when he was visiting Ner Yisroel, the gabbai called him up for an aliyah as Harav. Legend says Rav Shraga Feivel said to him, "You're giving me semicha?!"
In our shul, everyone is called up as "Rav" (not "Reb"), but 65% of us have semicha... RYBs gets called up as "Moreinu HaRav" despite qualifying for more (arguably). The Rav has three or more students in the shul who are practicing Rabbonim, Poskim and Roshei Chaburah, but they still get called as "Rav." Then last year, one of them was elevated to segan Rav of the shul, and now he is also called up as "Moreinu." Go figure...