I get that, but we can't prove anything beyond the people arrested. We can't know if the mob were immigrants, refugees, or citizens, and we certainly can't prove their religion.
The best place to start is with what we can prove-- those who were caught. If they turn out to be refugees, and I believe one is, then what is done to them says a lot about German policy. This will be irrefutable proof as to what they care about. If it's a slap on the wrist, then we can proceed from there with actual evidence that Germany is self-sabotaging. Until then, it's all speculation.