Some historians say that it was necessary for the Nazis to slowly ramp up anti-semitism (anti-Jewish behaviour) in order to achieve their goals. Why do you think this is?

it makes sense that to control the minds of a mass populist it would be nescessary to slowly desensitize them by introducing bits than over time increase the magnitude of exposure

Explanation:

its like the frog in the pot of boiling water thing: if you put a frog into a pot of cold water than put the pot on to a hot stove, the frog will not jump out if the pot as it does not notice or feel that it is getting hotter (because it is cold blooded, naturally) it will sit until the water bowls and kills it and us none the wiser. however if you simply put a frog into an already boiling pot of water, it will immediately sense the dangerous change in temp and jump out if the pot in an attempt to save it's own life.