I have no idea where the term began. It is, however, the term that Jews use to describe the “secular” calender that everyone uses. This article was from a Hebrew University website. Hebrew University is a Jewish institution. Ergo, Hebrew University is not going to identify any date as being “Before Christ,” because Hebrew University does not acknowledge that “Christ” (i.e. the Messiah) has ever come. Similarly, Hebrew University will not identify any date as “A.D.” (Anno Domini = In the Year of Our Lord), because Jesus is not, and never will be, “Our Lord.”
I don’t really feel insulted by the Jews not using the term, as you say, most of them (not all however) do not recognize yet that Jesus Christ is the Lord. Someday, you will though :)
It is still strange for the Jewish scholars to not recognize the terms however, the date range is the same...it is rather rude...don’t you think?
I wonder how you would feel if the insult were reversed...