Yes, all Germans are under attack. We are at war.
The war is being brought here. Do you really think no problems with a clash of cultures would be created? Refugees running from a country where they were attacked, houses destroyed, relatives killed, then they cross the sea with a shitty boat or go by foot for weeks? That does leave no marks that could cause anything bad? It is not like they paid 100€ and then went by plane, landed in Cologne, walked into the nearest hotel and settled down? No. Put away your weak glasses that show you a world that would and will never exist. Not everything is pink and nice, in this case nothing is.
Anyway, soon enough we'll see militias being formed and then the shit is going down. Hopefully. Seriously.