For over two thousand years....Germany's immigration problem involved only Germans....which is rarely detailed or explained by journalists today.
Through the Roman era, there are countless examples of villages or regions undergoing some radical challenges and violence...forcing the locals to make a decision to pack and leave the valley or the region. They might travel for a day or two....or for a week....to resettle and feel somewhat safer. In other words....they immigrated to someone else's valley or region, and 'integrated'.
When the Roman era ended, then came the Catholic Church era. Again, various episodes occurred, such as the burning down of the city of Wiesbaden by the Catholic Church leadership in Mainz....to trigger people into leaving or immigrating into another region.
Going to the 1505 period....a number of German craftsmen were recruited and brought into Russia, and they stayed.
Tsarina Catherine II of Russia opened up Russian borders around 1763, and had German colonies which developed around the Volga River.
Throughout the late 1600s and on up to the 1930s....Germans immigrated into the United States and Canada. For the US, the numbers go over eight million.
Oddly enough, it's not until you get to the late 1950s in Germany....that the reverse problem is finally noted....not enough manpower to operate German industry.
Solution? Germany opens up the door for Turks to come in on a green-card system and be employed. Some stay....most simply work a year or two and return.
Throughout the 1960s and 1970s....the only real immigrates are the Turks and a handful of southern European groups (Greeks, Yugoslavs, Italians, etc). No one says much.
As the Wall comes down, an odd thing begins to occur. Other nationalities, from Africa to the Middle East.....have decided to immigrate into Germany. For the first time in Germany history, you've a reverse situation. And these new Germans have varying habits and traditions....which aren't typical German.
With the birth-rate as it is today....without immigration....German society would begin to show problems and issues within the next thirty years. Fewer doctors, fewer technicians,less ability to adapt industry to new trends, etc.
The worst case of German integration? This is another little piece of German history which doesn't get brought up.
Adolph Hitler was an Austrian citizen all the way up to 1930. At the age of forty-one and dragging the Nationalist Socialist Party to the top.....he was a non-German. In 1930, the Nazi Party had been able to procure a win in Thuringia (an eastern state of Germany). One of their priorities was to place a Nazi Party individual within the state apparatus who could appoint police officers. There's a German law in effect at the time.....if appointed as a German policeman.....you automatically get citizenship.
The first attempt to appoint Hitler as a policeman was a failure. Nothing much is written over this. A couple of months pass, and the second attempt is successful. Without a integration test, or paperwork trail.....Adolph Hitler becomes a German citizen. Three years later, Hitler is Chancellor of Germany. You can write volumes over the comedy of a guy being appointed to his citizenship and three years later becoming the leader of a country.....but this is reality.
The odds of some new immigrant in Germany becoming Chancellor over the next couple of decades? It ought to be zero, but I'd take a humble guess that it'll happen within twenty years.
Bottom line? Germans haven't really had to view immigration into Germany....it's always been the opposite case. So, they might have adequate reasons to be apprehensive and question how this will turn out.