Because of the Immigration Act of 1965 pushed by Ted Kennedy who said at the time:
"I just want to make this point because the argument that the cultural pattern of the U.S. will be changed needs to be answered. Our cultural pattern will never be changed as far as America is concerned."Kennedy and the Democrat party saw this act as a free way to buy votes. Ted claimed that under 10,000 third world immigrants would arrive on our shores and then the influx would dry up.
I put into bold the reason why I asked the question. I am not oppossed to immigration, per se.