The scary thing is that it actually wasn't a lot of resources. Most genocides in history have happened in places that aren't industrialized. In those cases, yeah it did take a significant amount of resources and involves a lot of people.
For an an industrialized country, genocide on the scale the Nazis did is actually a tiny percentage of the resources available. Think about how many people you can put in just one train. Even if that train runs just a few times a day, well... there's some extremely dark mathematics about it.
The politics of hate is so incredibly dangerous in an industrialized country. Industrialized genocide can kill millions without impacting other priorities.