I asked R' Leff a question about Daas Torah relating to the Israeli elections before the last elections. Here is part of the question:
"...isn't it possible that the Gedolim are making a mistake? After all the torah has a parsha of Par Helem Davar shel Tzibur and in fact the gemara relates that the later Chachamim thought the R' Yochanan Ben Zacai had made a mistake when he just asked for Yavne, and they quoted a Pasuk "meishiv chachamim achor". In fact, just about all the gedolim in pre-WWII Europe were against people leaving and moving to America. Yet, in hindsight, it is clear that their opinion was wrong, those people who left (like my grandparents) survived and most of those who stayed perished. In short, could we not say that maybe today as well, the Gedolim are making a mistake in their view and a party like Herut, etc. is correct?"
You can listen to his answer here (it is only 3 minutes and a large part of it is reading my question). He says that even when the chachamim make a mistake we need to listen to them, this is hashem's will (this is how he understands "meishiv chachamim achor"). He implies that this is how we should view the Holocaust as well.
If you think about it he is most probably alive because his grandparents disregarded the Daas Torah and left Europe and moved to America. How does that fit in with what was the will of Hashem?