Firstly, I hope this was a joke but I'll run with it... I'm sure you mean emmigration is immoral. I still don't agree with this. Often people who emmigrate (from the 3rd world) send money back to their families, this financial support is crucial. Whilst not a 3rd world country, Cuba is kept afloat by money sent by ex-Cubans back to their families - possibly their biggest source of foreign currency.
Secondly, to condemn any one for moving to another country is crazy. People move for all sorts of resons - financial, political or even for a better climate.
Thirdly, I find your attitude somehat astonishing as you, Jesus, belong to a family of immigrants (you're not Native American, are you?).
I agree in part. Immigrants now have less incentive to adjust to another society. In the past, however, immigrants would live together and form small communities within the larger cities. Why else, for example, would you have the 'French Quarter' in a city, and so forth? The reason a lot of us don't think of that is that these 'quarters' were created hundreds of years ago and those immigrants have completely assimilated into society.
'Multiculturalism' is a valuable idea in some ways. I like, for example, that Britain almost certainly has the most vibrant 'fod landscape' in the world. When I went to America I was disappointed to only find shops that sold a 'curry.' Sorry, I didn't want a 'curry,' I wanted a Madras or a Tikka Masala or a Roghan Josh. In Britain, there are many places to get these in all major towns - we are tripping over them!
Go into any supermarket - the range of foods available is astonishing. Admittedly this is quite shallow - but it is a sign that things are changing. It takes small changes like this to successfully integrate other communities.
Also, I think this is Mexico's way of claiming land that was illegally taken from them... Perhaps we are witnessing the birth of the United States of Mexico. Desea México vivo!!!
