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.