This post and others of its kind are exactly why s_d is my favorite thing on the internet.
It's astonishing to see comics from the Forties that addressed Japanese-American internment camps (posted on the old community by strannik01; I wish I'd archived it) or Jim Crow laws or depicted Asians or Muslims with dignity. Mind you, having said that, it's also brain-twisting to realize that at the same time this was published, Steamboat was appearing in Captain Marvel stories. In a way, the more dignified and respectful stories make such racial cariacatures and stereotypes look even worse, because it removes the cheap excuse of "that sort of thing was taken for granted, they didn't know any better back then." Because we can find the evidence to say, no, some folks damn well knew better back then and created stories without racial stereotypes or slurs.
Also, seconding everything you said about the skill of the storytelling.