smerel,
goyim having behira is not problematic – as in deed Mitzrim chose to be more severe towards Yidden,
but saying that their behira is an exclusive reason for events with Yidden is. That would imply that Hashem does not make Jews the center of the story. So, Spaniards might have chosen to become prosecutors, or be harsher than expected, but there should be a Jewish reason for the events in general.
As to 20th century, it is probably not controversial that German assimilation caused hatred in a direct way, putting Jews into the center of German politics. And then there is downward spiral in observance in much of Eastern Europe. I would also add to that intra-Jewish relations of the preiod, with bitter infighting between political groups and lack of care for the klak Yisroel in general. this includes even care for German Jews when they were prosecuted… Some responded to an idea of a fast saying that it is impossible to fast for those who are not fasting themselves. [All groups ended up fasting in the camps, of course]. Even more so – abandonment of Russian Jewry after the Soviet revolution. Chofetz Chaim writes several times, calling for people to send packages during the hunger years and generally laments of their fate, and even reconsiders his decision to leave Soviet Russia and leave people behind without any guidance, but overall, there is no sense of Eastern European (or American) Jewry understanding the magnitude of physical and spiritual destruction of several million Yidden. There were individual efforts, such as saving R Moshe Feinstein, clandestine efforts by previous Lubavicher Rebbe, etc, but nothing comparing with 1970s movement for Soviet Jewry that took 50 years to start and that was still opposed by many of the Rabbonim.