I don't disagree that Germany needs skilled immigrants. But there is actually currently much less demand than some lobbyist claim and salaries are so low that mostly this is only attractive to 2nd class 3rd world immigrants. The very good ones go to the US, UK,CA or Australia immediately. Easier, much more pay.
Germany had immigrant waves from countries like Iran or Afghanistan some decades ago. But this were very highly educated people that fled due to the circumstances and were able AND WILLING to adapt.
The current African/Middle Eastern immigrants are not willing and probably not even able to adapt. "Harassment" was a polite correct way to speak of all the violence, rapes and sometimes murders that are committed.
Do you know the country with the highest cases of rapes? It is Sweden! Guess why? Yes, must be terrible people this tall blond Swedish Vikings raping their women....
Australia solved her immigration problem by just sending the people in the boats back home. Europe can not solve the problems of the world by accepting everyone that comes. In Germany, one of the most dense populated countries, alone 300.000-400.000 a year.
You can't have both. Free, unlimited immigration and social welfare. The people in Europe will have to make a decision about this.
Worse, this people are not solving their problems at home when they come but they import their problems into Europe.