Mary, I am not a Catholic . I was raised Presbeterian but today claim no faith except a strong belief that the Universe contains far more than what we can comprehend. As a child our minister always extended his arm while he was doing the benediction. I never before associated this with the nazi salute , but for sure the motion was the same although the intent was far different.
As a person with a strong Scottish heritage I have an understanding of the tradition of the "firey cross". This has also been stolen from our culture by assholes in the KKK , so that it means something far different from what it once stood for. From what you say, the same may happen to the blessing of the extended arm.
         Obie