I'm neither inclined to critique in detail nor am I tempted to endorse in whole McArdle's discussion of "microaggressions".
I will pull out one paragraph, because I think it shines a bright light on the way forward:
"A while back, when I wrote about shamestorming, I ended up in a Twitter discussion with a guy who chided me for letting my privilege blind me to the ways that minorities (specifically women in tech, and more broadly on the Internet), experience microaggressions. You know how that conversation ended? When I pointed out that he had just committed a classic microagression: mansplaining to me something that I had actually experienced, and he had not. As soon as I did, he apologized, though that hadn't really been my intent. My intent was to point out that microaggressions are often unintentional (this guy clearly considered himself a feminist ally)."
McArdle has mixed feelings about the apology. Miss Manners, I doubt, would not have and _I_ certainly don't. An apology is _absolutely_ the way to handle someone pointing out a microaggression, and Miss Manners' entire body of work was devoted to how to use the apology as a carefully honed tool which, like few other tools metaphorical or physical, can either build up and butcher -- or both.
The world has changed a great deal since the time when Miss Manners' columns were written and relevant, but we could sure use someone like her again today.