What I don't get is that if a writer put a foreign language in a comic without a translation, it's precisely to make the reader guess that some characters won't understand. So it put the reader in the same situation than the characters, which is very immersing. And if the reader understands the language, it does not matter, he will still understand the other characters don't.
I don't see the issue, or how there would be any justification for complain.
And German for an English speaker, frankly... I'm not even speaking about the fact they're both Germanic languages... Same alphabet, if it's so important to the reader to understand, it's just one automatic translation away.