Hi, Look I can't be bothered to go into the ethnotribal roots of English and the other island peoples, and Germans. Both are also complex intraethnically. EG: Eastern Germany / Brandenburg and then Prussia, was originally a slavic nation and much of the population there has Slavic roots (incl. more recently Polish) as well as Germanic, in contrast to the west, south west and north. Yes there is Anglo-Saxon ancestry - Germanic - through most of England. That's the male line, because the male Celts were mostly done to death. The females, however, founded the major ethnic background - Celtic - in England (as in most of the rest of the Isles, but not Germany). Just examples, there are many more. You did ask. All of this is discoverable, not without interest, but I'm not arguing for racial determinism (=racialism, racism) because family lines are only one and variable element in "peoplehood" / ethnicity. I suspect others are more invested in that dogma here.
I just think "nationalist language" is a blatent euphemism for racist language; I can't see how else to see that one. Yes you have insults with a familiar ethnic epithet (whinging Poms etc) but that doesn't make "pom" an insult in itself, does it. Modern people need to recall the distinction between adjective and noun!
I don't see the need to substantiate the difference between England (or whatever) and Germany by reference to culture. I think we belong the same super-ethnic conglomorate of western Europe which you might call Germano-Roman. The difference however is beheld, immediately, reflexively. It's a deeper phenomenon than the social. I think, biological: this perception of difference. That needs to be accounted for. Reduction of everything to means of production is for lobotomized fanatics (... who, amusingly, always have a keen nose for background and tend to fantasise their own.)
As for the rest: no argument, just my experience: normal, variable treatment by different ethnic groups here in London. I believe you live here too. Being looked at by a zoo animal when on the bus -e.g. Can't say it angers me but one notices it. More depressing (and I think connected) is the general breakdown of culture: fraternity, friendliness, "manners"; accessibility (of people to one another). I'm rambling. Ciao for now!