Why would any sane country let people who want to subvert that country in as immigrants or permanent residents?
Leftists aren't sane.
Not there. Not here. Not anywhere.
Neither in Europe nor in the US does the government ask its citizens what immigration policy should be.
Immigration policy should first, foremost, and always serve the interests of citizens. Immigration decisions should be made in the open and explained with respect to how it serves the interest of citizens.
This, of course, never happens.