I know what you are saying and you are right with the exception that the entire Anarchism movement of the late 19th century and early 20th was perpetrated by immigrants who absolutely refused to assimilate into this country. They caused havoc for many years. Emma Goldman, Alexander Berkman, Jonathan Most, the Haymarket “martyrs” and my favorite duo, Sacco & Vanzetti, were responsible for the murders of ordinary working people, employers, payroll guards, priests and politicians. So, there has always been gaps in our immigration policy. But nothing like today and happily, the government eventually cracked down on this criminal gang and deported most of the leaders.
I am aware of the element you’re talking about and I am pretty sure they didn’t form a majority of the people who came here at the turn of the century.