When quoting, the Guardian tends to provide "translations" in square brackets rather than editing what was said, which I think is the best compromise.
Regarding localisation of books, if I were an author of airport novels, bodice rippers, chicklit, etc, I would listen carefully to my publisher's editors on the other side of the ocean, whichever that happened to be, and in general take their advice. I would say to myself, "Those folks know their craft, and they know much better than I do what will sell, and that, after all, is the objective.". If, on the other hand, I had pretensions to be a writer of literature, I might very well dig my heels in. Personally I think that the word "literature" can only be applied to the output of J K Rowling very loosely indeed.
It's a funny thing though. I think I have read every single one of Ed McBain's 87th Precinct police novels, and the very Americanness of them is part of the pleasure, but I had to shut with a snap the only one of Patricia Cornwell's novels about her Kay Scarpetta character that I have tried to read.