You would think it would be the opposite. Hittler is a German surname. It is strongly associated with the Nazi leader Adolf Hittler. After World War II, many people born with the surname legally changed their surname.
The name “Mussolini” because of Benito Mussolini’s fascist regime, it’s extremely unlikely that a significant number of people in Europe, if any, are currently named Mussolini today.
Difference in cultures!