Obviously extremist attitudes don't disappear overnight when a regime promoting them disappears. Still, I would prefer to see a comparison to other parts of the world. Were antidemocratic, racist and antisemitic attitudes more common in postwar West Germany compared to other countries?
What is particularly lacking in research is perspectives from countries beyond Western world. Humankind's history is full of racism and xenophobia everywhere, but most research has a Western perspective.
Every study would be better if it were meta-analysis of longitudinal studies. But those cost a lot, and scientists make do with the resources at hand. But I think this study has value in its own right. I doubt this study was the only one looking at these sentiments during that time period; this is just the one that got posted today.
I think you can lay out your perspective as too narrow when trying to evaluate opinions and behavior and I believe this study has fallen victim to it, at least partially.
Racism played and still plays a huge part but the resentment against Jews was primarily caused because the Nazis convinced people successfully that they are the victims of a Jewish conspiracy around the world. The typical mechanism of populism. Of course this manipulation only works if a basic resentment already exists, which was true for Jews since time immemorial.
And this resentment did not vanish over night. I would argue that little of it remains today however. At least against Jews in Germany. There are of course very vocal exception. And it is a crowds that is indeed very dependent on outside confirmation.
What is particularly lacking in research is perspectives from countries beyond Western world. Humankind's history is full of racism and xenophobia everywhere, but most research has a Western perspective.