Before WWII, classical anti-Semitism had a range of beliefs that led the Germans and other Europeans during the war to murder millions of Jews under appalling conditions. What was it that the anti-Semites believed that was so terrible about the Jews:
1. The Jews were plotting to take over the world: this was a canard that was enhanced by the publication of “The Protocols of the Elders of Zion,” that was a forgery produced by a Russian official before WWI and that gradually gained popularity. It is still widely believed. The irony was of course that there was no such plot, it was a complete lie. But, it was the enemies of the Jews, the Nazis, then the Communists and now the Islamists, who make no secret of their intention of destroying Western civilization and replacing it with their own political and religious culture. They do want to take over the world.
2. The Jews control the media: Another nonsensical belief, since Israel gets such a bad press in the Western media, which is supposed to be free, let alone the Arab and other media. In fact, during the regimes of the Nazis and the Communists their media was obnoxiously controlled against Jews and now with the influence of Islam, the media is again strongly biased. The oil lobby in the US spends much more than AIPAC, and they use it to influence the media against Israel and the Jews. You have only to read the columns of Al Ahram in Egypt and watch Al Jazeera to see how Jews and Israel are constantly maligned.
3. Jews control international finance: The fact is that the Saudis make billions from their oil sales, yet it is the Jews who are accused of controlling the financial system. Arab oil money has been used to finance terrorism and certainly to support an international network of Muslim schools that teach the extreme form of Salafi Islam. It is Muslim money that undermines the West while Jewish money was and is emphatically part of developing the strength of the Western financial system.
4. Jews have too much influence in the professions: It was true that Jews were over-represented relative to their numbers as leaders of the professions of science, medicine and banking, etc. But, these greatly helped the development of the host countries. Spain and Germany in their time were dominant partly because of the Jewish contribution to their “golden age” and German science, respectively (note that Hitler referred to German science as “Jewish science”). But, when they expelled and/or murdered their Jewish populations these countries went into a decline from which they will never recover. This is the only topic in which the Muslims/Arabs cannot compete with the Jews.
The irony is that all the bad things attributed to the Jews that resulted in their being killed in great numbers, and that were untrue, are now being actually planned by the Islamic extremists. I would warn the Muslims pouring into Europe, that although the Europeans are currently very liberal, largely as a reaction to their former extreme murderous hatred, they can turn on you, just as they turned on the Jews.