"... you scoff at the thought that visiting alien spaceships could manage faster-than-light travel and come to this planet."

one--more--time.... scoffing is not the same thing as skeptical thinking! One involves denial, the other involves doubt.
It is similar to the difference between atheism and agnosticism. Doubt might be measured by the amount one is willing to bet in certain circumstances, while denial might be measured by "unwillingness to take a fool's money" ;>)

and I suspect that in 1822 I would have gotten in a LOT of trouble by refusing to accept the racial stereotyping you refer to. I remember in 2nd grade being told by my mother (in New Orleans) "Don't put that nickel in your mouth, a n***** might have handled it." I thought that seemed silly, even then, although I didn't know how to debate Mom at the time.

And I 'think' I would have been one of those, going back to Leonardo, who said, "birds can fly, some squirrels can glide...why not us?". I used to analyze Superman and Captain Marvel comic books by explaining that Superman was based on scientific theory, while Capt. Marvel just referred to 'magic' and let you guess how reciting "Shazam" could give you special powers!...Oh, I was wearing on my parents and teachers, I wAS!

There is stuff I might be willing to bet on, simply because there are other explanations that, to me, seem more likely....and as I say, there are bets I'd really like to lose!