Lee Martin McDonald (in the afore-cited article) suggests that intimidation was one factor in sharpening Christian polemics against Judaism. Jews were, after all, vastly more numerous than Christians: “By the turn of the first century, those who counted themselves among the Christians were probably fewer than 100,000 throughout the Roman Empire, but at the same time the Jewish population was somewhere between six and seven million, which was approximately one seventh to one tenth of the entire population of the Roman Empire . . . . By any estimates, the Christians in their first two hundred years and probably longer were greatly outnumbered and quite possibly intimidated not only by the numbers of Jews in the empire, but also by their large buildings, like those at Sardis, and their long-standing influence and protected privileges in the Greco-Roman world. Further, there is no certain evidence that the Christians significantly outnumbered the Jews in the century following the conversion of Constantine.” No wonder Christians were scared when Julian proposed to rebuild the Jerusalem temple: Not only would this refute a long-standing Christian apologetic (concerning AD 70), but it would empower Jews that probably still outnumbered Christians by a large factor.
McDonald cites an old article by Robert Louis Wilken in support of his claim that the Jews continued to outnumber Christians into the early fifth century. Citing Marcel Simon’s Verus Israel: A Study of the Relations between Christians and Jews in the Roman Empire (AD 135-425) (Littman Library of Jewish Civilization) 
“the book showed that during the period from 135 to 425 Judaism, far from coming to an end, was a real, active, and often effective rival and competitor of Christianity.” Philo boasted that Jews “attract and win the attention of all, of barbarians, of Greeks, of dwellers on the mainland and islands, of nations of the east and the west, of Europe and Asia, of the whole inhabited world from end to end. For who has not shown his high respect for that sacred seventh day . . . . Again, who does not every year show awe and reverence for the fast . . . . That the sanctity of our legislation has been a source of wonder not only to the Jews but also to all other nations is clear both from the facts already mentioned and those which I proceed to state.”
It was no idle boast, Wilken concludes: “Judaism made great gains in the Mediterranean world during the late republic and early empire. It must have grown enormously, as the passage from Philo implies. Every indication we have from ancient sources confirms the statements of writers such as Philo and Josephus. Even the satirist Juvenal, who frequently held up the Jew to ridicule, once remarked that some Romans abstain from pork and observe the sabbath and that their sons are circumcised and study the Torah of the Jews. And Josephus said that ‘the masses have long since shown a keen desire to adopt our religious observances, and there is not one city, Greek or barbarian, nor a single nation, to which our custom of abstaining from work on the seventh day has not spread, and where the fasts and the lighting of lamps and many of our prohibitions in the matter of food are not observed.”
This is the setting for much of the early Christian vituperation of Jews: Jews were numerous, well-established, and admired by many Romans; the church was tiny, vulnerable, sometimes hated and persecuted. For the early Christians, this was unnatural; it ought not be that the Jews, who had refused Jesus and whose temple was long destroyed, should not only survive but succeed.