I think the author is too hard on themselves for not knowing things, probably coming from shame. I can only speak for myself but learning to shrug that off just how to say "I don't know X" or "I forgot X" is very freeing. I say I don't know shit all the time at work, and so do people I work with. We aren't encyclopedias. Just chuckle about it and figure it out and learn.
I much prefer working with people who can just be honest about what they don't know, it's way better than pretending to know or trying to save face, and generally people in the former camp seem to have higher EQ.
It’s so hard to ask people how git rebase works during an interview. They tend to assume you want the intricate technical details, which, while fun to know, completely miss the point. The only thing I care about is whether you can use the tool well enough that I don’t have to spend any time reconstructing branches :P
For some reason I'm able to say "I don't know" to coworkers and superiors at work with no problem, but I have a much harder time online where it may affect future employers' opinions of me.
My boss actually said that to me once. He said he really appreciated that I would say "I don't know" instead of bullshitting him. Of course I would also try to brainstorm with him or find the answer later on by searching.