Most of the discussion in here is over validity of commenting to scientific journalism, but I have something to say about it in regards to creative work. Particularly, what the Viheart video made me think of. When she talked about being confident in your work and sharing it because you made something, reminded me of something my childhood mentor told me around the time I made the leap to adulthood. It was about love.
She told us (my class, with me drawing somewhere off in the second row...) about true love. She said that when you're young you often find someone who makes you comfortable, or maybe excites you, and you want to shout to the high heavens "You complete me!" But that's mostly... well, hormones.
To truly know true love, you must first complete yourself. Once you know who you are, really know who you are, and gain an appreciation and love for yourself and all the confidence and humility that comes with it, then you're ready to love someone else. She said it wasn't fair to put the pressure on someone else to 'complete' you. You just met! You just started dating! You've known one another for like three months! That's three month compared to the 16 years we had all known ourselves. It wasn't fair, and it wasn't true.
I took that to heart, and stopped looking for outward approval, and began looking for it within myself. The happy result there is regardless to my point.
My point, is to apply this to both posting and commenting. When a creator feels complete, comments don't make or break them. Obviously Viheart is there. When you don't feel valid, probably because no one told you that you could validate yourself (or maybe you did and something horrible happened that you now must confront), you'll look for ways to feel valid, such as creating and being loved, tearing apart something someone else has created, or finding someone (or something) to 'complete' you. But once you do the work to find out who you are, those compulsions dissipate.
Am I saying to stop creating or posting until you've validated yourself? No. Just do it in the context that you know you need to be a little easier on yourself and a little more self-loving.
Am I saying you need to take yourself out for a romantic, candle-lit dinner, just you and your beloved self? It seriously couldn't hurt.
And as a preemptive strike to those who have someone who completes you while knowing you yourself are complete, I say: When you say they complete you, what you really mean is you are complete, and they are complete and together the two of you kick so much ass that you never want to be without them again because seriously, you and this person rock all kinds of awesome. It's okay to say it. Cuz you (and I) know what you mean.