No it isn't. US history has multiple cases of Irish-Italian ghettos in the 19th century. And what about all the Chinatowns out there? Those are enclaves of Chinese culture and Chinese immigrants (and their descendants) in the United States.
The "melting pot" was an idealized concept that never actually happened. Otherwise, you wouldn't see American citizens wearing saris or eating pizza.
You're really going to compare modern U.S. immigration policy and practice to what it was in the 19th century? That's a bit unfair. If anything, we have gotten better at assimilating immigrants over the years. I can tell you that modern immigrants in general face much less discrimination and abuse than my ancestors did when they came over from Italy and Eastern Europe a little over a century ago.
And as far as Chinatowns are concerned, modern Chinatowns are more commercial and cultural attractions than "ethnic enclaves". You don't typically see immigrant communities in the modern USA looking down on outsiders--it's bad for business, after all.
1. As an Italian-American, I know for a fact that immigration quotas were used against my family (dad, aunt, uncle, and grandparents are off-the-boat Italians) as recently as 1952. That's not the 19th century.
2. Look up "sundown towns." Very common in the 19th and early 20th centuries. Black people and Chinese-Americans weren't allowed within city limits after the sun went down--effectively ensuring that only WASPs lived in those particular towns.
3. Have you seriously not heard of the insanely stringent anti-immigration laws lately?
4. Wow, for someone trying to school people on U.S. history, you know jack squat about Chinatown. Also, just because people are nice to you to your face, doesn't mean they aren't nasty to you behind your back. Not singling out the Chinese-American community here, just saying it happens.
5. Please stop calling people names. It's not cool.
(EDIT: Was off by a year. My dad was young at the time, but not quite that young.)
