"Be yourself" doesn't really mean anything. I do agree with your assessment of the healthiest interpretation of the advice, and I think this is how people mean

"Be yourself" doesn't really mean anything. I do agree with your assessment of the healthiest interpretation of the advice, and I think this is how people mean to use it. That said, plenty of people misinterpret the advice to justify not changing too, and that's what the article means to address.