I doubt that Steve Bannon used the term “far right”. My guess is that Google Translate is taking liberties.
“...estrema destra in Europa...”
...the extreme right in Europe...” In this case, it’s not “Google’s fault” at all, the translation is precise.
My guess is that the interview was conducted in English (does Bannon speak Italian?) and then translated into Italian for Il Corriere della Sera; if such was the case, the word choice was that of the interviewer/reporter, not Google.