This is well meaning advice but it makes the mistake of believing the block to engineers attaining charisma is a lack of knowing how to do it. In reality, what you see is primarily an emotional reaction, where they find emotional justifications for why this advice is not right for them.

I find what's often unacknowledged is just how much interest in technical matters is driven by a trauma response. A lot of us were unpopular as children or were ostracized for being weird and attaining mastery over an "objective" arena allowed us to feel better about our place in the world.

Asking people like that to "just be charismatic" is asking them to depart from a safe space and enter into an arena they've previously associated with a lot of unpleasant emotions. People will act out in ways that feel are perfectly "rational" for them but are coming from places they're unable to explain because they're driven by more primal urges.

For the advice to stick, you have to address the root cause which is the emotional, not the informational need. Otherwise, you're going to see the same well meaning advice go around in circles with only a minority of the field being motivated to act on it.