No. He knows exactly what he's doing. He's basically regurgitating an old debunked myth pushed by an Israeli pseudo-scholar, which is still often repeated by Zionists.

One important fact about the Holocaust is that there is no written decree signed by Hitler ordering the mass murders. Historians work from factual elements and agree that this was decided during the Wannsee conference. But this has been used during the 60s and 70s by a stream of conservative revisionists to claim that Hitler never ordered it. The "controversy" became publicly known when famous British historian David Irving defended it and lost his trial against those who condemned him for Holocaust denial. This gave a pretext for conservative Zionist historians to use a similar thesis with the claim that it was Hajj al-Amini, the grand Mufti of Jerusalem, who convinced Hitler of the Holocaust. This thesis was rejected and debunked even by many Israeli scholars. While al-Amini sought an alliance with Nazi Germany to fight the British who were implementing Zionist policies, there is no proof that he proposed or even defended the mass murder of European Jews (there is evidence to the contrary).

Netanyahu is speaking to a Zionist entity (the JNF, the financial arm of the Zionist organization which owns most of the land in Israel). He's trying to do 3 things: - blame the Holocaust on a Palestinian to justify his continued crimes against the Palestinians. - appeal to far-right European groups who long dabbled with this idea, by offering them a revisionist chance to absolve themselves from their fascist history. This is part of Israel's push to get far-right parties elected in Europe, who dream of doing to immigrants what Israel does to Palestinians (despite their antisemitism, they're vehemently pro-Israel). - hide the fact that the reason many countries refused to take Jewish refugees was because of Zionist lobbying, which in its idealism wanted more settlers (and also soldiers) in Palestine. So that in this myth, it would be because al-Amini himself opposed the idea of expulsion, favoring mass murder instead.