I have to say, that I agree with all this in some degree or another. I have posted items in the critique section and expected criticism, if i don't want critisism then I post in the show off section (although I still expect some criticism). I think if someone says you could do this better then I listen, If they say you suck then I figure they don't like it. No biggy.
I have been fortunate to grow up in an area where criticism is freely given, and our sense of humour revolves around taking the mickey out of each other. So I am not overly sensitive, but helpful criticism is always welcome.
One thing I do find difficult, is to get my point across, without sounding like an Arse especially when I am tired. I often reword posts several times and end up deleting them before I post, or afterward (in one specific case) finding that they sound mean or unhelpful. I am new(ish) to leather but have been an artist, woodland crafter, bushcrafter for a long time. All the forums I have attended I have ended up putting my foot in it, at least once (or twice).
Ah ha moments are really important especiaslly when backed up with knowledge of someone who has done it before.