First, I don't accept your assertion that mass immigration is not a real thing. You should show how it is not. Second, the large wave of immigrants that came to Europe recently...
it was sold to us as refugees, but later it has been shown that the majority was not. Many go back to their home countries on vacation for example. Those who were refugees from long
ago, they mostly stay in the European countries even when wars stop in their home countries. They have not plans to go back. Very different from majority of WWI/II refugees
Whether it is a bad thing or not is not relevant. The point is it is different. Taking care of a group for a short while is very different from being stuck with them forever
Those who dont return often left because of persecution. Those who return left because their homes were not safe. They are more likely to return after.
So, I will use my parallel again. I let you stay in my house for 1 hour because you are cold. Then I demand that you now let me stay in your house forever. Fair?
Also, you really should read up on demographics for the region. Some estimates give muslim majority in about half a century. If you look at what trouble they already have with distinct
minorities, this is a very serious thing. Again you should watch the movie I linked to. It shows some of the things you can expect with radical Islam in a western country