The killer is that powerful and wealthy people from the Middle East know that their antisemitism is not normal to the rest of the world. They go to incredible lengths to sanitize their English media, and ex-pats studying or immigrating to the EU or the US are careful to not mention the horrific things people said around them, daily, about Jews (or women, America, gay people, or Black people).
But if you know someone honest from the Middle East, or know someone that speaks Arabic, or even just study the Middle East or browse Middle Eastern state-sponsored media with Google translate turned on, you will see it. It's not a secret. But it might as well be, the way the UN and Western NGO complex pretends it does not exist at all.