Europe jewish population in 1933-1935 wasn't even 10 million at that time, it was about 9.5 million at maximum.
If the Holocaust did not happen and, let us say that almost every jew in Europe moved to Israel (2025's population: about 10 million), where did all those jews go? Europe had the greatest jewish population in the world, and now it is gone! How could that happen if not by a great extermination? I'm no zionist nor good goyim, but the Holocaust DEFINITIVELY happened.