So your argument is that because you say I'm wrong, I'm wrong? Glad we got that cleared up.
Nationalist language: referring to the Germans as krauts came about when soldiers from the U.K. Were pitted against the Germans. As such, like every insidious piece of soldier training (to allow the easy killing of others), it's nationalist language. Racist? No more than the others I mentioned. I've heard '####ing yank' more often than as you suggest in a friendly or familiar manner. I've heard 'whinging pom' more often than it used in any friendly manner too. And so on.
You need to work on your argument. Saying yes to someone's no isn't an argument, it's iust a contradiction.