Definitely wasn’t intending to imply that you are good or bad at anything, just wanted to make sure I pointed it out as a reason people are paid more or less for labor :)
It’s definitely good that you’re encouraging people not to work for free, but this isn’t something that requires such a lengthy missive. What I take issue with is “Apart from promoting free labour, you impede the designer from earning a proper salary. Would you work for free with the hope of possibly being compensated?” and your title, which implies moral failing on behalf people that do work for free or organizations that take advantage. They are actors who are simply acting rationally to economic incentives.
I’m glad you brought up photography — it’s actually something I’ve written about on this very topic: http://quietlife.net/2010/01/30/the-oversaturated-sky-is-falling/