"That may be so - but it is also irrelevant."
- Col. Nguyen Don Tu
It is very relevant, because many preachers in the Church continually try to use that label 'Jew' for ALL... Israelites, when that is not Biblical nor historical. They don't realize it's the 'crept in unawares' that are pushing them to spread that lie.
Per the Jewish historian Josephus (circa 100 A.D.). Below he was talking about how Nehemiah had received a letter from the king to take back to the governor Adeus of Syria, and Phoenicia, and Samaria, to rebuild Jerusalem's walls and the temple, and for the governor to supply Nehemiah with whatever he needed.
7. Now when he was come to Babylon, and had taken with him many of his countrymen, who voluntarily followed him, he came to Jerusalem in the twenty and fifth year of the reign of Xerxes. And when he had shown the epistles to God 13 he gave them to Adeus, and to the other governors. He also called together all the people to Jerusalem, and stood in the midst of the temple, and made the following speech to them: "You know, O Jews, that God hath kept our fathers, Abraham, and Isaac, and Jacob, in mind continually, and for the sake of their righteousness hath not left off the care of you. Indeed he hath assisted me in gaining this authority of the king to raise up our wall, and finish what is wanting of the temple. I desire you, therefore who well know the ill-will our neighboring nations bear to us, and that when once they are made sensible that we are in earnest about building, they will come upon us, and contrive many ways of obstructing our works, that you will, in the first place, put your trust in God, as in him that will assist us against their hatred, and to intermit building neither night nor day, but to use all diligence, and to hasten on the work, now we have this especial opportunity for it." When he had said this, he gave order that the rulers should measure the wall, and part the work of it among the people, according to their villages and cities, as every one's ability should require. And when he had added this promise, that he himself, with his servants, would assist them, he dissolved the assembly. So the Jews prepared for the work: that is the name they are called by from the day that they came up from Babylon, which is taken from the tribe of Judah, which came first to these places, and thence both they and the country gained that appellation.
(The Antiquities of the Jews, by Flavius Josephus, Book XI, Chapter 5, Section 7.)
Once God had scattered the northern ten tribes of Israel out of the northern portion of the holy lands, the Jews of the southern "kingdom of Judah" were the only ones left. And those of that southern "kingdom of Judah" (see 2 Chron.11), only, became known as the Jews, that title taken from the sole tribe of Judah. Only the tribes of Benjamin and Levi were joined with Judah in that kingdom at Jerusalem-Judea. The kings of Assyria had replaced the northern ten tribes with pagan foreigners from Babylon in the northern holy lands at Samaria, and those became the Samaritans.
So is that relevant? Yes indeed, it is very relevant to both Bible history and secular history.