It’s not “rude.” It is, however, extremely rude for you to demand that any Jew, especially a Jewish scholar, define any year as being “Before Christ,” when no “Christ” has come. It’s no insult, unless you are insulted by us uppity Jews not toeing the line and converting. In which case, you can, once again, copulate with yourself. We ain’t going anywhere.
Of course it is rude, and it is dishonest. The facts are that the date ranges are the same...whether you understand that Jesus Christ is God or not is irrelevant at that point...the dates reflect his birth/death. It is an insult to try to steal that from people.
I had the honor of witnessing an afternoon prayer by Orthodox Jews. It was an amazing event, the history of this prayer service going back thousands of years and still being conducted to this day in the same manner with same words (I presume anyway) was incredibly moving. Now, I do not worship the same way...afternoon prayers...nor do any Christians I know of...not in the same way. But, it would be an incredible insult and rude to change the name of what you call it for something non-Jewish say. I know these are somewhat apples to oranges, but there are similarities.
In any event, I am really tiring of this thread. I have been subjected to rudeness and name calling, of course by people who would not have the courage to say these things to my face. So, I will bid you adieu and good luck.