Why does St. Paul rebuke his own Jewish race?

St. Paul rebukes the Jews because they neglected the central role they were meant to play, which is to preach the Messiah to which the Old Testament’s symbols and prophecies testify . In other words, their proper task was not to haughtily and vainly engage in foolish disputes against the gentiles, but to preach the faith to them. This is what the apostle Paul meant by saying, “How then shall they call on Him in whom they have not believed? And how shall they believe in Him of whom they have not heard? And how shall they hear without a preacher? And how shall they preach unless they are sent? As it is written: ‘How beautiful are the feet of those who preach the gospel of peace, who bring glad tidings of good things.’” (Rom. 10:14–15).