A few weeks ago, all scholarship pointed to a young, white, solitary white male as the Beltway shooter.
Our ancesters assimiliated because they HAD to. They also WANTED to, by and large. They didn't have the privilege of bringing their country with them with full financial support of the host country.
I wholeheartedly endorse generous immigration laws. We need and want lots of legal immigrants--from many countries!--, coming in an orderly and lawful fashion. But now the first experience immigrants have is scoffing and shrugging and disrespecting those same laws, rebuffing even the friendly communities in which they find themselves, even while making free use of all the services that are supported by those communities.
The present situation will lead to dislocations and many stresses.
This irrelevant comment aside, I'm not sure you and Luis disagree on much.