Earlier quoted context omitted.
What is the difference? Give examples of vulnerability that is not also weakness.
I prefer to use the term "open" instead of vulnerable, to avoid exactly the situation you're pointing out. And you can be open without being weak or vulnerable if you have self-confidence. Not faked confidence, but the genuine kind that comes from dealing with your shit instead of repressing it and putting on a mask of fake confidence, strength, stoicism, invulnerability, etc.
But if all you ever do is only talk about topics that you can confidently speak about with out risking something, then you are missing out on something. And sure you can also go and deal with it on your own till you got the confidence to talk about it without exposing yourself, but there are connections you will be never able to form if all you ever do is deal with yourself.