Speaking of history books, you would do well to read some. Pay attention to one thing in particular: the number of times that leaders proclaimed a racial or religious conspiracy by a different group in order to justify oppression, war or genocide, vs the number of times such a conspiracy really existed.

The first number, you will note, is quite large. The second is zero.

This is not to say that history isn't full of atrocities. The point is that they are invariably inflicted by those who have power onto those who don't. The twisted claims of white supremacists are typical of powerful people trying to stoke paranoia, usually to justify terrible things that follow.