No, the Ghetto Vecchio came later, in 1541. The word was first used to describe Ghetto Nuova.
Wendell Wagner, Ronald Takaki, in A Different Mirror: A History of Multicultural America, would probably disagree with this, although it’s true that the years after the Civil War did not coincide with any of the major influxes of immigration that normally set off the worst waves of bigotry. He’d certainly disagree that blacks or Chinese were ever integrated into mainstream society. Only the tiniest minority were. In fact, the Chinese Exclusion Act was passed in 1882 during Loewen’s accepting period.
It’s therefore technically true that prejudice against Jews was much lower before 1890. That’s because there were very few Jews in the country before then. Those who were tended to be from Germany. German Jews were the leaders in the Reform Judaism movement, and were normally more assimilated, more urban, better educated, wealthier, and less “different.” They moved easily into society, at least to a point, in both Germany and America. (That was a major reason why the Jews of Germany could not believe the danger they were facing once the Nazis came into power.)
The large wave of Jewish immigration came after the Tsar forced all Russian Jews to move into the Pale of Settlement and took away their rights to own land. They were forced to rent in highly overcrowded cities and set up shops that competed against one another for the limited audience. In addition, there were virtually yearly pogroms against them. They started moving to the U.S. in the 1880s. By 1905 the Lower East Side in New York held 500,000 Jews in the most crowded slum in world history. Before World War I, a full third of all the Jews in Eastern Europe and Russia had fled, knowing they could never go back. (Unlike, say, Italian immigrants, as many as a third of whom returned to Italy after making money (or failing) in America.)
These were shtetl Jews, mostly peasants despite forced into cities, with the backwards ways and customs that later became the stereotypical Jew. All the people who push the nonsensical proposition that Judaism is a culture rather than merely a religious belief are looking at this one, admittedly large, group and declaring it to be what Judaism is. German Jews hated them with the insider hatred that rivals anything outsiders can bring. German Jews, Sephardic Jews, Arabic Jews (Baghdad held a community of 400,000 Jews until after WWII), Chinese Jews, Ethiopian Jews, and many others, not to mention converts, put the lie to this stereotype.
But the stereotype did feed prejudice, and their numbers along with the numbers of Italians, Greeks, Poles, and other eastern and southern Europeans forced Congress to pass the Immigration Act of 1924, effectively cutting off the mass migrations, by setting the quotas to the census ratios of immigrations as of 1890. That alone gives the best indication of how few “undesirable” immigrants were in the country at that time. Without the new crush of competitors for jobs and the fact that WWII wiped out unemployment, these older prejudices could begin to fade, making room for the new set against Mexicans and Asians today.