The C.S. Lewis quote above (the one I replied to) is from
Mere Christianity. As to whether the original quote is relevant to this Quillette story, your guess is as good as mine.
Later
I'm being coy, because I don't believe most people who deploy this quote have read Mere Christianity, which is ungracious of me (and technically a violation of our guidelines). So: to put it more directly:
Lewis isn't asking people to be skeptical of wrongdoing. The quote is from an essay on forgiveness. That chapter explicitly references the harm Germans inflicted on Poles and Jewish people. Lewis isn't skeptical of that harm (to say the least), and he's not exhorting people towards skepticism of wrongdoing in general.
What he's saying is that you should be careful not to attribute to random people, by dint of their belonging to some specific group, the worst possible harms you can come up with. And he's saying that you shouldn't because it's an impediment to the Christian virtue of forgiveness; to love your neighbor as yourself, you need to love your imputed enemies as yourself, and to do that you have to find a way to forgive them their transgressions against you, and, more immediately, the transgressions of their groups.
I quoted the paragraph immediately following the quote offered (in implicit support of skepticism, as that quote is almost always used). I could just as easily have quoted the paragraph that immediately precedes it:
Consequently, Christianity does not want us to reduce by one atom the hatred we feel for cruelty and
treachery. We ought to hate them. Not one word of what we have said about them needs to be unsaid.
But it does want us to hate them in the same way in which we hate things in ourselves: being sorry
that the man should have done such things, and hoping, if it is anyway possible, that somehow,
sometime, somewhere, he can be cured and made human again.