Post-WW2, the Grand Mufti's disciples continuously attacked the nation of Israel. In 1972, his health failing, the Grand Mufti passed the torch of hate for Jews and Israel to his nephew, Yasser Arafat. Al-Husseini went room temperature in 1974. Presumably, he, his nephew, and the rest of Hitler's cronies are warmly received in Hell.
I think the author’s point is that Haj Amin al-Husseini’s hatred for the Jews predated the Nazi era, although he clearly saw the advantages of joining forces with an evil ideology that went hand in glove with his own genocidal goals.
Netanyahu is also pointing to Jew-hatred as intrinsic to Islam, with the Nazi era incidental to that fact.
That the Palis are & have been completely Nazified since the 1930’s is obvious. Mein Kampf in Arabic is a bestseller in the region to this day.
The twin poisons of Naziism & Islam are totally & inextricably intermingled and will never be separated.