Whether kraut is derogatory in the same manner as yank, Pom, kiwi, etc, or whether it's derogatory in a worse manner (let's say calling someone a piece of shit), it's hard to see how it's racist, since racially the uk and Germany are traditionally the same, culturally they're traditionally similar. Might be considered nationalist language, and the sort of thing I personally avoid, because I don't like name calling of any sort, but like suec I'd say we should be careful about what we label racism lest we diminish actual sufferers of real racism by using it willy nilly. When it's referencing a white European woman (one of the most powerful people in Europe at that), I think racism is probably the incorrect term. I've had plenty of Brits call me a convict, and it's never once occurred to me they were being racist against white Australians. Rather, they were just making boring and unoriginal references to historical likelihoods.