it doesn't matter whether you call them "German" or "people whose ancestors hail from the region of modern Germany". they are unique people, ethnically and culturally different even from their neighbors, let alone from those being imported from all around the world to suppress their wages and keep their rents high.
it's not controversial, for example, to say that Ukrainians and Russians are different people. the intent behind equating our superficial similarities to us being "one people" is obviously malicious. likewise, it shouldn't be controversial to say that Europeans and South Americans/Asians/Africans/etc are different people. the notion that Hassan ibn Hassan from Mogadishu magically becomes a German if he moves to Frankfurt is as absurd as the notion that Hans Hanssen from Frankfurt would magically become a Somali if he moved to Mogadishu.
it's not controversial, for example, to say that Ukrainians and Russians are different people. the intent behind equating our superficial similarities to us being "one people" is obviously malicious. likewise, it shouldn't be controversial to say that Europeans and South Americans/Asians/Africans/etc are different people. the notion that Hassan ibn Hassan from Mogadishu magically becomes a German if he moves to Frankfurt is as absurd as the notion that Hans Hanssen from Frankfurt would magically become a Somali if he moved to Mogadishu.