Because national socialism is based on the foundations of human existence.
As we evolved, over millions of years, human beings learned that settling in a fruitful geographic region with family members was the safest and most efficient way to survive. We hunt and fight for our genetic kin. If needed, we migrate with our kin to new lands. We become attached to the land, having spent hundreds and thousands of years settling and developing it. We base our culture on this land and on our own people, all genetically related to us. We live and enjoy such an existence because the survival of our kin means the survival of ourselves for many hundreds of years in the future.
National socialism is based on preserving our ancestral lands and uniting as genetic kin within these lands, and creating an economy of resources and culture that serve its existence without parasitism and infighting.
It's a political system that "just works" because it serves us in the exact way that we once served ourselves, for thousands and millions of years. Everyone in their heart craves national socialism.