A man starves his own people and threatens to start a nuclear war, and Americans laugh. What a bizarre thing to do.
Partly it’s the way they present themselves. North Korea is a relatively small nation with leaders who come across as stereotypically incompetent Bond villains: uniformly dressed, tasteless but expensive cliché obsessions, physically unintimidating, with every major attack blowing up in their face like Wile E. Coyote. The Kim family does not produce tall or physically gifted men, nor exceptionally handsome ones. They are also Asian, which connotes a whole set of racist stereotypes, none of them necessarily terror-inspiring. Iran, meanwhile, is a Muslim nation, and for obvious but unfortunate reasons it’s easier to stoke public fears of Muslim fanaticism than Northeast Asian nationalism.
Thus the reasons are not so surprising.