This theory would not explain the settling (by the Gospel of John and in the Acts) on "the Jews" denoting not merely people of Jewish ethnicity but specifically the Pharisees, unconverted Jews in general, and Jews scheming to kill Jesus and His disciples in particular.
Paul’s entire post-conversion life is utterly incompatible with a man who believed that the Torah had been abolished by the coming of Christ or that keeping the Torah’s commands or maintaining Jewish identity were incompatible with life under the Gospel.
No one Catholic is saying that the Torah was "abolished" or Jewish distinctive habits are "incompatible". Rather, the Torah is fulfilled in the Gospel of Grace, and can only be understood through it, and the circumcision and the kashrut are of no relevance. Certainly you are familiar with the verses written by St. Paul to that effect.
Gentilizing to Jews is every bit as much a false gospel
You mean Jewish converts? Have they not read "there is no distinction of the Jew and the Greek" (Romans 10:12, similar Galatians 3:28)? Or you mean Jews by religion? If so, I am sure it would, but in general conversion to Christianity is not an easy step for anyone; it is after all dying to self.
Since Christianity has defined itself [...] as a new religion that actively demands the assimilation of Jews
Ethnocultural Jewishness is of no relevance, but conversion to Catholic or Orthodox Christianity is certainly required of everyone, Jew or Greek.
After much reflection in my earlier years, Annalex, I'm fairly convinced that when John uses the expression "the Jews" that he is referring to the leadership of both Sadducee and Pharisee. Obviously, he didn't mean "of Jewish descent", because that would be talking about himself also.
I'm also convinced that the Apostle Paul AFTER his conversion, AFTER his guidance gained from the Council of Jerusalem, and AFTER having spent his calling in telling Gentiles to turn to Christ Jesus without having to obey the Jewish law, that he himself saw no contradiction with continued observance of his Jewish traditions. Buggman is right. Paul clearly went through the Nazirite vows on his return to Jerusalem. He saw no contradiction in maintaining his Jewishness EXCEPT when it came to Peter's hypocrisy in pretending he was not associating with Gentiles.
As xzins has already pointed out, people back then wrote in extremely broad terms and expected their audiences to pick up that they were talking about the leadership in particular.
Heck, we do that even today: We can talk about how "the Germans" invaded France during WWII, but obviously it was the Nazi leadership that made the decision and a minority of Germans who were actually in the military carrying out the orders.
Moreover, it is the Christians who have persecuted, robbed, tortured and murdered the Jews for the last two thousand years. By your own standards, your hands are soaked with blood, your churches are filled with stolen treasures, your national governments are built on robbery in the form of unpaid loans going back thousands of years.
Remember: "For with the judgment you pronounce you will be judged, and with the measure you use it will be measured to you. Why do you see the speck that is in your brother’s eye, but do not notice the log that is in your own eye? Or how can you say to your brother, ‘Let me take the speck out of your eye,’ when there is the log in your own eye? You hypocrite, first take the log out of your own eye, and then you will see clearly to take the speck out of your brother’s eye" (Mat. 7:2-5).
Finally, those who were persecuted by "the Jews" in the NT were Jews themselves. How dare you use their sufferings as an excuse to hate their people whom they themselves loved! And how dare you hypocritically attack those who persecuted the Jewish disciples of the Messiah when you yourself do the exact same thing!
Shalom.
You mean Jewish converts? Have they not read "there is no distinction of the Jew and the Greek" (Romans 10:12, similar Galatians 3:28)?
Have you not read that there is also "neither male nor female" (Gal. 3:28)? Does this mean that homosexual unions are now permitted, since there's no distinction? And why then does the Catholic Magesterium deny the priesthood to women, if indeed all such distinctions are done away with?
Moreover, have not not read, "Was any man called when he was already circumcised? He is not to become uncircumcised. Has anyone been called in uncircumcision? He is not to be circumcised" (1Co. 7:18) and that, "Then what advantage has the Jew? Or what is the benefit of circumcision? Great in every respect" (Rom. 3:1-2)?
Since it is obvious that you have no problem with someone being a Roman Catholic or a Greek Orthodox or an American Christian, and since you recognize that even though men and women are saved by one Lord there are still distinctions between them, you once again betray your double-standard and theological anti-Semitism.
Paul says that there is no more Jew nor Gentile in the matter of salvation. You twist that and claim that there is no more Jew.