Ha! I knew I should've said "so few" and not been so hyperbolic. Yes, there are exceptions. But even with the movies you mentioned - "Das Boot" was originally a TV miniseries, not a movie (although it was released as a movie internationally afterwards), Downfall I wouldn't classify as a war movie but as a Hitler biopic [at least not the kind of war movie I was thinking of, where the perspective is the one of the common soldier], and "Sophie Scholl" takes place during the third Reich, but I wouldn't call it a war movie, either (stories of resistance instead of the soldiers is exactly the kind of movie I meant that was more representative of the discourse here). Joyeux Noel is mainly a French movie (shared production with quite a few countries including Germany, and obviously with some German actors but with a French director).
The Bridge and Stalingrad are great examples, and there are of course a few others (quite a lot from the sixties, if you count TV movies), but we're talking seventy years of movie history here, and the fact remains that they're few and far between, compared to how popular a genre this is in other countries.