Himmler had theories of the occult and those played into his decision and his leadership that ultimately led to the slaughter of millions of people. Himmler was not a small player in the German regime, and if he thought these things, it very likely influenced his philosophies and ultimately the policies of Germany in World War II.
Heinrich HImmler was Hitler's SS chief. According to dailymail.co.uk, he had amassed an extensive library (13,000) of occult books, and he believed that "mysticism was proof of Aryan racial superiority." As a powerful figure in the Third Reich, surely his views influenced the Fuhrer and therefore contributed to the horrors of the Holocaust.
Many nazi leaders had some occult leanings. These included those on race. But Jews would still be hated with or without these beliefs based on their actions. Himmler believing more fringe things was certainly not a thought shared by all the nazis and magic doesn't and didn't effect the war or the holocaust. If the nazis could use magic to control things, why didn't they win the war?
Hitler was an absolute dictator and whatever he said went. Whatever Himmler believed about witchcraft was minor compared to the fact that he followed Hitler's orders. If Hitler wanted the Holocaust, then so be it. It was done. The witchcraft books had nothing to do with it, except maybe the minor fact that they allowed Himmler to rationalize his going along with Hitler's wishes.
I guess it's a theory someone could ponder if they wanted to and maybe if I read this book I might feel differently. The thing is in some ways we are witnessing what caused the Holocaust first hand which is frightening. Hitler wanted to blame all Jews for the actions of a certain amount of them. Now in the world we live in today we are turning on another religious group for the actions of some who hide behind the faith doing horrendous thing and that of course is the Muslim faith. So, the cause of the Holocaust for me was fear and anger along with allowing our own hatred to get the better of us, I just hope we don't fall into that trap again.