I take all your points, Howie, but it still boils down to whether or not you believe that somebody else knows better than you do what you were trying to do.
I have to admit that there is room for instruction (as distinct from criticism) in matters such as technical competence - I think that was implied in my post - but one imagines that by the time people are posting their stuff online or otherwise submitting it for viewing that they will long have reached the point where they know what they are doing, where they want to go and how to get there. So, in that context at least, asking for criticism is more or less redundant: you have the tools, know how to use them, so what else can another person do for you? In my opinion, not a lot; they certainly can't teach you how to be an artist. That, I'm afraid, is in your genes or it isn't.
Ciao - Rob C