The craziest thing about the holocaust is, it’s so mentally disfiguring that it always ends up leaving the person unable to see reality and live in a world of fantasy. In many cases (such as this one), that particular mind virus is an outgrowth of real psychic collapse.
The tiniest germs of truth mixed with giant helpings of total nonsense, and everything becomes a piece of the grand narrative you began with. Surprise!
They end up folding everything into one big, irrefutable conspiracy theory because that’s the only way their brains can accommodate the enormity of their obsession.