Plenty of people of all political stripes were, are, and have been complaining about immigration. It was a key factor in Brexit.
Cooper's deliberate misreading of the Wannsee Conference is Nazi apologeticism.
"Well, they didn't really mean to commit genocide, they just whipped up public hatred, confiscated all their assets, and banned them from working! So of course they had to commit mass murder!"
Who are his sources, David fucking Irving?
And let's not get started on the pipelining of extremist views to people who would normally consider themselves moderate or centre-right and are now spouting insanity...
Cooper also claims that the Holocaust happened by mistake, so I wouldn't pay too much attention to him.