I guess anyone can interpret it however they want. If you’re challenging yourself in your career, you will eventually find yourself in a position where you legitimately don’t know what you’re doing, and people are depending on you to figure it out. Early in my career I thrived in these situations, because they mirrored my experiences in college. Later in my career, the problems got bigger and I found myself wondering if I would ever figure these things out, saying to myself, maybe I’m actually not smart enough, maybe I took the wrong career path? But, if you keep your composure, read the docs, ask the right people for help, you figure it out and move on. I always assumed that’s what people meant. Seems like young people today have much more anxiety that we used to though, so maybe the definition has shifted.
I think your description seems pretty spot on. But the way I see the term being used sometimes, it seems some people take it as some sort of shame-but-actually-pride badge (the connotation being that if you have the syndrome, then you're secretly not an impostor, hence a "humble brag")
IMHO, you could leverage that uncomfortable feeling positively (e.g. seeking the right people to help you, etc as you said), negatively (e.g. give up) or in a beside-the-point way (bragging about the cup being half-full). None of this has really anything to do with acting maliciously/destructively like the article seems to suggest, though.
