Thank for the link. I am suprised you chose the passage on the two sets of brothers, as in context it is fairly orthodox. It analogizes the concept of spiritual adoption without actually claiming that the Jews are NOT of Isaac and Jacob. My previous remark is more to the interpretation that you were giving than to the excerpt itself.
I did not read it closely, but some of the conclusions toward the end cannot please a Jew, and they are unorthodox. It is not the position of the Church that the Jews and Christians should not mix, not have equal civil rights, or that Christianity and Judaism are in some kind of cosmic unending struggle. I read the fathers of the Church daily, and I do come across some strong language, but it is always confined to the historical conflict between Jesus and the Pharisees and the persecution of the Church immediately after that.
Whether or not Frs. Michael Crowdy & Kenneth Novak are at liberty to express their private exegesis as Catholics is not for me to say, but I can see how it could be problematic.
This is indeed the stated teaching of the Catholic Church. It has been repeated many times. Here for example is an encyclical by Pope Benedict XIV (the same pope who wrote an encyclical condemning usury):
http://www.papalencyclicals.net/Ben14/b14aquo.htm
We adopt the same norm of action as did the Roman Pontiffs who were Our venerable predecessors. Alexander III forbade Christians under heavy penalties to accept permanent domestic service under Jews. "Let them not continually devote themselves to the service of Jews for a wage." He sets out the reason for this in the decretal Ad haec, de Judaeis. "Because Jewish ways do not harmonize in any way with ours and they could easily turn the minds of the simple to their own superstitions and faithlessness through continual intercourse and unceasing acquaintance." Innocent III, after saying that Jews were being received by Christians into their cities, warns that the method and condition of this reception should guard against their repaying the benefit with evildoing. "They on being admitted to our acquaintance in a spirit of mercy, repay us, the popular proverb says, as the mouse in the wallet, the snake in the lap and fire in the bosom usually repay their host." The same Pope stated that it was fitting for Jews to serve Christians rather than vice versa and added: "Let not the sons of the free woman be servants of the sons of the handmaid; but as servants rejected by their lord for whose death they evilly conspired, let them realize that the result of this deed is to make them servants of those whom Christ's death made free," as we read in his decretal Etsi Judaeos. Likewise in the decretal Cum sit nimis under the same heading de Judaeis, et Saracenis, he forbids the promotion of Jews to public office: "forbidding Jews to be promoted to public offices since in such circumstances they may be very dangerous to Christians." Innocent IV, also, in writing to St. Louis, King of France, who intended to drive the Jews beyond the boundaries of his kingdom, approves of this plan since the Jews gave very little heed to the regulations made by the Apostolic See in their regard: "Since We strive with all Our heart for the salvation of souls, We grant you full power by the authority of this letter to expel the Jews, particularly since We have learned that they do not obey the said statutes issued by this See against them"
And to show that this was not a new or eccentric opinion, he quoted some of the many previous papal bulls that had said the same thing:
It is enough to peruse decretals with the heading de Judaeis, et Saracenis; the constitutions of Our predecessors, the Roman Pontiffs Nicholas IV, Paul IV, St. Pius V, Gregory XIII and Clement VIII are readily available in the Roman Bullarium. To understand these matters most clearly, Venerable Brothers, you do not even need to read those. You will recall the statutes and prescripts of the synods of your predecessors; they always entered in their constitutions every measure concerning the Jews which was sanctioned and ordained by the Roman Pontiffs. I read the fathers of the Church daily, and I do come across some strong language, but it is always confined to the historical conflict between Jesus and the Pharisees and the persecution of the Church immediately after that.
Perhaps your reading hasn't extended to St. John Chrysostom. Here are texts of his 8 sermons against the Jews in which he said things like:
But do not be surprised that I called the Jews pitiable. They really are pitiable and miserable. When so many blessings from heaven came into their hands, they thrust them aside and were at great pains to reject them. The morning Sun of Justice arose for them, but they thrust aside its rays and still sit in darkness. We, who were nurtured by darkness, drew the light to ourselves and were freed from the gloom of their error. They were the branches of that holy root, but those branches were broken. We had no share in the root, but we did reap the fruit of godliness. From their childhood they read the prophets, but they crucified him whom the prophets had foretold. We did not hear the divine prophecies but we did worship him of whom they prophesied. And so they are pitiful because they rejected the blessings which were sent to them, while others seized hold of these blessing and drew them to themselves. Although those Jews had been called to the adoption of sons, they fell to kinship with dogs; we who were dogs received the strength, through God's grace, to put aside the irrational nature which was ours and to rise to the honor of sons. How do I prove this? Christ said: "It is no fair to take the children's bread and to cast it to the dogs". Christ was speaking to the Canaanite woman when He called the Jews children and the Gentiles dogs.http://www.fordham.edu/halsall/source/chrysostom-jews6.html(2) But see how thereafter the order was changed about: they became dogs, and we became the children. Paul said of the Jews: "Beware of the dogs, beware of the evil workers, beware of the mutilation. For we are the circumcision". Do you see how those who at first were children became dogs? Do you wish to find out how we, who at first were dogs, became children? "But to as many as received him, he gave the power of becoming sons of God".