回答: 因为唐人街的存在是早在共产党还没有成立之前 由 ABC888 于 2015-06-02 9:00

In the years after the United States enacted the Immigration and Nationality Act of 1965, allowing many more immigrants from Asia into the country, the population of Chinatown increased dramatically. Geographically, much of the growth was to neighborhoods to the north. The Chinatown grew and became more oriented on families due to the lifting of restrictions.[42] In the earliest years of the existence of Manhattan's Chinatown, it had been primarily populated by Taishanese-speaking Chinese immigrants and the borderlines of the enclave was originally Canal Street to the north, Bowery to the east, Worth Street to the south, and Mulberry Street to the west.
 
Immigration reform in 1965 opened the door to a huge influx of Cantonese speakers from Hong Kong and Guangdong province in Mainland China, and Standard Cantonese became the dominant tongue. With the influx of Hong Kong immigrants, it was developing and growing into a Hong Kongese neighborhood, however the growth slowed down later on during the 1980s-90s.[48][49]
 
Development stages[edit]
 
Through the 1970s-80s, the influx of Guangdong and Hong Kong immigrants began to develop newer portions of Manhattan's Chinatown going north of Canal Street and then later the east of the Bowery. However until the 1980s, the western section was the most primarily fully Chinese developed and populated part of Chinatown and the most quickly flourishing busy central Chinese business district with still a little bit of remaining Italians in the very north west portion around Grand Street and Broome Street, which eventually all moved away and became all Chinese by the 1990s.[50][51][52]
 
Until the 1980s, the eastern portion of Chinatown east of the Bowery, which is considered part of the Lower East Side was developing more slowly as being part of Chinatown, the proportion and concentration of Chinese residents was lower and more scattered than the western section, and there was still a higher proportion of Non-Chinese residents than Chinatown's western section consisting of Jewish, Puerto Ricans, and a few Italians and African Americans.[53]
 
During the 1970s and 1980s, the eastern portion of Chinatown east of the Bowery was a very quiet section, and like in all of the rest of the Lower East Side, many people and especially many Chinese people were afraid to walk through or even reside on the streets east of the Bowery due to deteriorating building conditions and high crime rates such as gang activities, robberies, building burglaries, and rape as well as fear of racial tensions with other ethnic people that were still residing there. In addition, there were fewer businesses and there were significant amount of vacant properties not occupied.[54] Chinese female garment workers were especially targets of robbery and rape a lot on their way home from work and often left work together as a group to protect each other as they were heading home.[55][56][57][58][59] In May 1985, a gang-related shooting injured seven people, including a 4-year-old boy, at 30 East Broadway in Chinatown. Two males, who were 15 and 16 years old and were members of a Chinese street gang, were arrested and convicted.[60][61]
 
Starting in the 1970s and especially throughout the 1980s-90s, Mandarin-speaking Taiwanese immigrants and then later on many other Non-Cantonese Chinese immigrants also were arriving into New York City. However, due to the traditional dominance of Cantonese-speaking residents, which were largely working class in Manhattan's Chinatown and the neighborhood's poor housing conditions, they were unable to relate to Manhattan's Chinatown and mainly settled in Flushing and created a more middle class Mandarin-Speaking Chinatown or Mandarin Town (國語埠) and even smaller one in Elmhurst, since most of the newer upcoming generations of ethnic Chinese were already using Mandarin although still their regional dialects in everyday conversations, whereas Cantonese speaking populations largely don't speak Mandarin or only speak it with other Non-Cantonese Chinese speakers. As a result, Manhattan's Chinatown and Brooklyn's emerging Chinatown were able to continue retaining its traditional almost exclusive Cantonese society and were nearly successful at permanently keeping its Cantonese dominance.
 
However, there was already a small and slow growing Fuzhou immigrant population in Manhattan's Chinatown since the 1970s-80s in the eastern section of Chinatown east of the Bowery, which was still underdeveloped as being part of Chinatown.