Please do not discuss the “reasons” or who is “to blame” for the Holocaust – we simply do not have the ability to understand it. But we can react. And IMO the way a Jew can respond is to strongly embrace the Torah and halacha and attempt to bring as many other Jews closer to Torah observance as he can. Have children and raise them as Jewish educated Torah lovers. Increase the number of Torah true Jews in the world any way you can.
Please do not discuss the reasons for the Holocaust.