The Paris attacks led people to question which immigrants are admitted to Europe, and by extension which immigrants are allowed into the US. It seems like leftists the world over prefer to admit immigrants that are opposed to Western ideas and denounce Western Civilization.
All leftists hate Western ideas, either openly or covertly. It isn’t so surprising leftists want to import more folks who also hate Western ideas. It's also not too surprising that leftists are so stupid they can't see what the end game looks like when unassimilated minorities want to change the countries they live in to look more like the countries they came from. But the problem is not immigration itself. The problem is the combination of immigration and multiculturalism.
The US needs educated self-supporting immigrants that assimilate. We don't have enough children on our own to prevent demographic collapse. We need the smartest people possible to maintain our technological edge. But immigration is one area where we absolutely need diversity. Too many of any one group means that group doesn't have to assimilate. They can just stick together as an undigested lump and insist everyone else adjust to them.
The traditional melting pot model of immigration actually works. My grandfather's family were Jews from Budapest. His life-long friend was a cowboy born in Montana who spoke Danish at home growing up. My grandmother's family were a mixture of late 1890’s English immigrants and Huguenot (Protestant) French who had been in this country for so long I don't know when they first got here. Despite very different backgrounds, it all worked very well.
We should not let leftist idiots' multicultural manure force us to abandon what has worked for us for over two centuries. It's the multiculturalism that's the problem, not immigration.