The actual net number of immigrants into Germany in 2015 was estimated at 1.1 million, not a few tens of thousands as you claim. Are you making up numbers again, Collapse Bro?
Your made-up low estimate is a failed attempt to hide a problem that is on display all over Europe: the economically unsustainable contradiction in having a huge set of social benefits and a vast flow of new immigrants. The problem is that the new immigrants receive benefits from a system they did not contribute to. Governments need to borrow more to sustain the benefits. Eventually they start unraveling the safety net.
When they come in such numbers, the immigrants overwhelm the ability of countries to absorb and integrate them into the existing national cultures. Many if not all countries in Europe are fundamenally based on ethnicity. Add in too many immigrants of a different ethnicity and a different culture, and the demographic change becomes a crisis of identity. Is France actually France if French become a minority minority there? As long as migrants buy into American culture and the American Dream, the US has less of a problem than countries in Europe have in absorbing migrants. But what is the point of highlighting the difference? Populist sentiment to control immigration has been dramatically increasing on both sides of the Atlantic.