Why have Germans historians opted to broaden the narrative? I can only imagine. A common story I hear of people growing up in Germany in the 60s, 70s and 80s was that there were a whole list of questions that you weren't allowed to ask your (Grand-)parents. You knew they were in Hitler youth, maybe even in the Wehrmacht or heaven forbid the SS. I do not know about you, but when I was young I asked all kinds of questions. Most of these historians were probably the same, and decided to make their career out of these unanswerable and taboo questions. What we have today, as a result, is a much more complex, nuanced, and complete understanding of the decisions of our grandfathers. This nuance might seem dangerous to you? Should nuance be illegal? Yes, even violence has a context. Perhaps this sense of threat stems from the cultural difference of viewing "Committers of Crime vs Criminals". I won't speculate further.
In closing, it is important to note that what I have provided in my original comment is not revisionist in the sense you seem to be suggesting. The facts are unchanged and undisputed. It is the perspective on the facts that have shifted, with the distance provided by time. I hope we can distinguish between the two, and therefore agree that I was not changing the picture of 1945 (revisionism), but filling in the picture of 1941-45 (contextualizing). There's a sizable difference!