Earlier quoted context omitted.
Not to diminish any of the other claims but I found this one to be a bit of an eye roller - Describing another incident, she wrote, "I was walking back to my cube from the break room and passed a group of managers exiting a meeting. The Area Manager told me to smile as I walked past." "While this is a small thing, it was notable as this is one of the most commonly reported forms of subtle sexism." No matter how hard…
By asking/telling someone to smile, one is basically saying, "You should look more pleasant for my benefit." I can't see asking someone to smile being appropriate in a workplace setting unless the person is in a customer-facing role and it affects job performance. The sexist part is that it seems to happen far more often to women than to men.
It's equally possible that it was intended as a shorthand for "cheer up, it's not that bad" or "try to keep your chin up". Both of which actually indicate that the speaker cares about their colleague.
Sure, I can see contexts where it would be inappropriate to say but that doesn't make it always inappropriate to say.